U.S. patent application number 16/008672 was filed with the patent office on 2019-01-17 for switching materials, and compositions and methods for making same.
This patent application is currently assigned to SWITCH MATERIALS, INC.. The applicant listed for this patent is SWITCH MATERIALS, INC.. Invention is credited to Neil Robin BRANDA, Glen Ramsay BREMNER, Jeremy Graham FINDEN, Simon James GAUTHIER, Bronwyn Hilary GILLON, Andrew KOUTSANDREAS, Veronica Elizabeth MARSHMAN, Matt Andrew PILAPIL, Jonathan Ross SARGENT, James Daniel SENIOR, Karthik Vikram Siva SHANMUGAM.
Application Number | 20190018295 16/008672 |
Document ID | / |
Family ID | 49326970 |
Filed Date | 2019-01-17 |
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United States Patent
Application |
20190018295 |
Kind Code |
A1 |
BRANDA; Neil Robin ; et
al. |
January 17, 2019 |
SWITCHING MATERIALS, AND COMPOSITIONS AND METHODS FOR MAKING
SAME
Abstract
A switching material comprising one or more than one polymers
and an electrolyte comprising a salt and a solvent portion
comprising one or more solvents; and one or more compounds having
electrochromic and photochromic properties dispersed homogeneously
through the switching material; and wherein the switching material
is transitionable from a light state to a dark state on exposure to
UV light and from a dark state to a light state with application of
an electric voltage.
Inventors: |
BRANDA; Neil Robin;
(Burnaby, CA) ; BREMNER; Glen Ramsay; (Burnaby,
CA) ; FINDEN; Jeremy Graham; (Burnaby, CA) ;
GAUTHIER; Simon James; (Burnaby, CA) ; GILLON;
Bronwyn Hilary; (Burnaby, CA) ; KOUTSANDREAS;
Andrew; (Burnaby, CA) ; MARSHMAN; Veronica
Elizabeth; (Burnaby, CA) ; PILAPIL; Matt Andrew;
(Burnaby, CA) ; SARGENT; Jonathan Ross; (Burnaby,
CA) ; SENIOR; James Daniel; (Burnaby, CA) ;
SHANMUGAM; Karthik Vikram Siva; (Burnaby, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SWITCH MATERIALS, INC. |
Burnaby |
|
CA |
|
|
Assignee: |
SWITCH MATERIALS, INC.
BURNABY
CA
|
Family ID: |
49326970 |
Appl. No.: |
16/008672 |
Filed: |
June 14, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14391491 |
Oct 9, 2014 |
10054835 |
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PCT/CA2013/000339 |
Apr 9, 2013 |
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16008672 |
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61706001 |
Sep 26, 2012 |
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61673470 |
Jul 19, 2012 |
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61621736 |
Apr 9, 2012 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02F 1/153 20130101;
G02B 5/23 20130101; G02F 1/0063 20130101; G02F 2202/14 20130101;
G02B 1/04 20130101; G02F 2001/164 20190101; G02F 1/0126 20130101;
G02F 1/15165 20190101 |
International
Class: |
G02F 1/153 20060101
G02F001/153; G02F 1/01 20060101 G02F001/01; G02F 1/15 20060101
G02F001/15; G02B 1/04 20060101 G02B001/04; G02F 1/00 20060101
G02F001/00; G02B 5/23 20060101 G02B005/23 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2012 |
CA |
PCT/CA2012/000910 |
Claims
1.-46. (canceled)
47. A switching material comprising: a. one or more than one
polymers; b. an electrolyte comprising: i. a salt; and ii. a
solvent portion comprising one or more solvents; c. a sacrificial
solvent; and d. one or more compounds having electrochromic and
photochromic properties dispersed homogeneously through the
electrolyte, wherein the switching material is transitionable from
a light state to a dark state on exposure to light comprising
wavelengths of about 420 nm or less and from a dark state to a
light state with application of an electric voltage.
48. The switching material according to claim 47 comprising, on a
weight basis: a. about 2 wt % to about 15 wt % polymer; b. about
0.1 wt % to about 5 wt % salt; c. about 50 wt % to about 90 wt %
solvent portion; d. about 0.5 wt % to about 15 wt % of a compound
having electrochromic and photochromic properties; and e. about 1
to about 3 equivalents of sacrificial solvent to total polymer,
salt, solvent portion and compound having electrochromic and
photochromic properties, by weight.
49. The switching material according to claim 47 further comprising
a crosslinking agent.
50. The switching material according to claim 47 wherein the one or
more than one polymers are crosslinked with a crosslinking agent or
with the crosslinking agent and an accelerant.
51. The switching material according to claim 47 wherein the
switching material is soluble in the sacrificial solvent.
52. The switching material according to claim 47 wherein the
switching material comprises from about 1.5 to about 2.5
equivalents of sacrificial solvent to total polymer, salt, solvent
portion and compound having electrochromic and photochromic
properties, by weight.
53. The switching material according to claim 47 wherein the
sacrificial solvent has a boiling point at least 50.degree. C.
lower than the solvent portion and is non-reactive with the one or
more than one polymers, the salt, the solvent portion and the one
or more compounds having electrochromic and photochromic
properties.
54. The switching material of claim 47 wherein the one or more than
one polymers is a polyol, a polyvinyl acetal, a polyvinyl butyral
or a combination thereof.
55. The switching material of claim 47 wherein the one or more
polymers is a polyvinyl butyral having one or more of: a MW of from
about 100 to about 300 k, a polyvinyl alcohol group content of from
about 18% to about 21%, a polyvinyl acetate content of from about 0
to about 2.5%.
56. The switching material of claim 47 wherein the salt comprises a
TFSI or BF.sub.4 anion.
57. The switching material of claim 47 wherein the salt comprises
an organic cation and the organic cation is a tetraalkyl ammonium,
a tetraalkylphosphonium, a dialkylimidazolium, or a
trialkylimidazolium cation, and wherein alkyl includes a group of
from 1 to 10 carbons.
58. The switching material of claim 47 wherein the electrolyte has
a potential range of from about -1.0V to about +1.5 V compared to
an Ag/AgCl reference electrode.
59. The switching material of claim 47 wherein the solvent has one
or more of the following: a. a boiling point of about 150.degree.
C. or greater; b. a vapour pressure of about 0.001 mmHg or less at
20.degree. C.; c. a Yellowness Index (YI) of about 6 or less; d. a
flash point of about 80.degree. C. or greater; and e. a melting
point of about 40.degree. C. or less.
60. The switching material of claim 47 wherein the solvent portion
comprises one or more than one of dimethyl 2-methylglutarate,
1,2-butylene carbonate, 1,2-propylene carbonate,
2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, diethyl succinate,
diethyl adipate, dimethyl adipate or a combination thereof.
61. The switching material of claim 47 wherein the crosslinking
agent comprises one or more isocyanate groups.
62. The switching material of claim 47 wherein the one or more
compounds having electrochromic and photochromic properties is a
diarylethene.
63. A method of making a switchable film comprising the steps of:
a. providing a first part comprising one or more polymers, a salt,
one or more compounds having photochromic and electrochromic
properties, and a first portion of the solvent portion; b.
providing a second part comprising a second portion of the solvent
portion, an optional crosslinking agent and an optional hardener;
c. providing a third part comprising a sacrificial solvent and an
optional accelerant; d. combining the first part and the second
part; e. combining the third part with the combined first and
second parts to provide a coatable composition; and f. applying the
coatable composition to a substrate to form the switchable
film.
64. The method of claim 63 wherein step f) is preceded by a step of
partially curing the coatable composition.
65. The method of claim 63 wherein step f) further comprises curing
the coatable composition.
66. A method of making a laminated glass comprising: a. preparing a
switchable material according to claim 47; b. applying a layer of
the switching material onto a first substrate; c. applying a second
substrate to the layer of the switching material; d. curing the
layer of the switching material to form a switchable film; e.
positioning the switchable film within a stack of components
comprising at least one layer of a hot-melt adhesive contacting an
outer surface of the switchable film; f. heating the unlaminated
stack to a temperature of from about 90.degree. C. to about
140.degree. C. for at least 30 minutes.
Description
RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. application Ser.
No. 14/391,491, filed Oct. 9, 2014, which is a National Stage
Application of PCT/CA2013/000339, filed Apr. 9, 2013, which claims
the benefit of U.S. Provisional Application No. 61/621,736 filed
Apr. 9, 2012; and which claims benefit of U.S. Provisional
Application No. 61/673,470 filed Jul. 19, 2012; and which claims
benefit of U.S. Provisional Application No. 61/706,001 filed Sep.
26, 2012; and which claims benefit of PCT Application
PCT/CA2012/000910, filed Sep. 28, 2012, all of which are
incorporated herein by reference in their entirety. To the extent
appropriate, a claim of priority is made to each of the above
disclosed applications.
FIELD
[0002] The present disclosure relates to a switching material
having electrochromic and photochromic properties, the switching
material comprising a polymer, an electrolyte and one or more
switchable compounds. The present disclosure further relates to
compositions and methods for producing such a switching
material.
BACKGROUND
[0003] A variety of materials or systems with variable light
transmitting qualities are known, including electrochromic
materials, suspended particle displays or screens, electrochromic,
photochromic and thermochromic materials, and those that are
hybrid--having two or more of photo-, electro- or thermochromic
qualities. The materials may vary from solid, liquid, gel or the
like, the particular state and composition of the material may be
dependent upon, or limited by, the needs of the particular system.
For example, the material may need to be conductive or insulative,
may need to solubilize all components or only selected components
of the system, and may further need to be tolerant of chemical
transitions occurring with the material to achieve the light
transmitting qualities. The chemical, electrochemical or molecular
environments that may be suitable may vary greatly with the
specific needs of the system.
[0004] Polymers may be used in such materials to provide structure
or support, modulate rheology to aid in handling or manufacture, or
to render the material in a suitable shape (e.g. be cast, extruded,
coated or molded). Selection of the polymer(s) may be dependent on
the intended use of the material, or in view of particular desired
characteristics (e.g. photochemically inert, sufficiently high, or
low, glass transition temperature, or the like.
[0005] The flowability of some polymer-containing systems may be
modified by heat. While this may be advantageous for some
manufacturing processes (e.g. injection molding, casting or the
like), if the molded or cast material is subjected to temperature
variations when in use, this characteristic may be undesirable in
the final product.
[0006] A material that does not flow or alter shape with heat may
be useful for some applications--resistance to flow may be imparted
to a material by increasing the viscosity of the material, or
solidifying the matrix, e.g. by crosslinking of one or more polymer
species within the material. A variety of methods are generally
known for creating intermolecular cross-linkages of polymers.
Selection of a method, and/or particular reactants, may be
dependent on an intended use or function, or desired
characteristics of the composition or material comprising the
cross-linked polymer, function of other components in the
composition or the like. For example, some methods may include a
condensation reaction, which may produce water, an alcohol group,
an amine group or the like. Depending on the uses, the presence of
these groups may adversely affect the durability or performance of
the composition, or the function of another component in the
composition.
[0007] It may be advantageous to incorporate materials with
variable light transmitting qualities into laminated glass ("safety
glass"). Some of these materials may be degraded, or some aspect of
performance reduced, when subjected to the temperature and pressure
of conventional glass lamination.
SUMMARY
[0008] A composition with reduced, or absent, temperature-induced
flow may be a useful addition to the art. Where the composition
includes a crosslinkable polymer, the ability to cure at reduced
temperature, or without generation of radicals, or release of
species that may be detrimental to performance of the composition
may be advantageous. A material supportive of both photo- and
electrochemical reactions for reversible interconversion of a
chromophore between a faded state and a dark state conformations
may be a useful addition to the art.
[0009] In accordance with one aspect, there is provided a switching
material comprising: one or more than one polymers; an electrolyte
comprising a salt and a solvent portion comprising one or more
solvents; and one or more compounds having electrochromic and
photochromic properties. The one or more compounds may be dispersed
homogeneously throughout the switching material. The one or more
compounds may be dispersed homogeneously throughout the
electrolyte. The switching material may be transitionable from a
light state to a dark state on exposure to UV light. The switching
material may be transitionable from a dark state to a light state
with application of an electric voltage. The one or more than one
polymers may be crosslinked with a crosslinking agent; the
crosslinking reaction between the one or more than one polymers and
the crosslinking agent may be facilitated by an accelerant. The
crosslinking agent may comprise one or more epoxide groups, one or
more aldehyde groups, and or one or more isocyanate groups.
[0010] At least one of the one or more than one polymers may be a
polyol; the polyol may be a polyvinyl acetal. The polyol may be
polyvinyl butyral (PVB). A PVB may have one or more of a MW of from
about 170 to about 350 k, or any amount or range therebetween; a
polyvinyl alcohol group content of from about 12 to about 21%, or
any amount or range therebetween, or from about 12 to about 18%, or
from about 12 to about 16%, or from 18% to about 21%; a polyvinyl
acetate content of from about 0 to about 4%, or any amount or range
therebetween, or from about 1 to about 4%, or from about 0.5 to
about 2.5%.
[0011] The electrolyte may have a potential range of from about
-1.0V to about +1.5 V compared to an Ag/AgCl reference
electrode.
[0012] In some aspects, the switching material may comprise one or
more of about 2 wt % to about 15 wt % polymer; about 0.1 wt % to
about 5 wt % salt; about 50 wt % to about 90 wt % solvent portion;
and about 2% to about 15 wt % of a compound having electrochromic
and photochromic properties. The switching material may comprise
about 70 wt % to about 90 wt % electrolyte. A solvent of the
electrolyte may have one or more of a boiling point of about
150.degree. C. or greater; a vapour pressure of about 0.001 mmHg or
less at 20.degree. C.; a Yellowness Index (YI) of about 6 or less;
a flash point of about 80.degree. C. or greater; and a melting
point of about 40.degree. C. or less. The solvent may, when
combined with a chromophore, have a change in Yellowness Index of
about 6 or less after 250 hours of weathering.
[0013] The solvent portion may comprise a first and a second
solvent. The first and second solvents may be present in
approximately a 1:1 ratio. A first solvent of the solvent portion
may be present in about an equal amount to that of a second
solvent. In another aspect, a first solvent may be present in from
about a 2 fold to about a 1000 fold greater ratio, relative to a
second solvent. In some embodiments the first and second solvents
may be present in a ratio of from about 1:1 to about 1000:1, or any
range therebetween. In some aspects a solvent portion may comprise
3 or more solvents. The one or more solvents and their relative
quantities may be selected, alone or in combination with one or
more salts, to solubilize switching material components, provide a
suitable electrochemical environment to switch the switching
material when a voltage is applied and/or provide a suitably
photostable switching material.
[0014] In accordance with another aspect, there is provided a
switchable film comprising a first and optionally a second
substantially transparent substrate, a first and a second electrode
disposed on the surface of at least one of the substrates; and a
switching material disposed between the first and the optional
second substrates and in contact with the first and the second
electrodes.
[0015] In accordance with another aspect, there is provided a
method of making a switchable film comprising preparing a switching
material, applying a layer of the switching material onto a first
substrate, applying a second substrate to the layer of the
switching material and curing the layer of switching material.
[0016] In accordance with another aspect, there is provided a
method of making a switchable laminated glass (heat-laminated)
comprising preparing a switchable film, positioning the switchable
film within a stack of components comprising at least one layer of
a hot-melt adhesive contacting an outer surface of the switchable
film, and heating the unlaminated stack to a temperature of from
about 90.degree. C. to about 140.degree. C. for at least 30
minutes. The unlaminated stack may be subjected to at least a
partial vacuum before the step of heating. The step of heating may
further include application of pressure. The pressure may be from
about 50 psi to about 90 psi. The hot melt adhesive is
polyvinylbutyral, polyurethane or ethylvinyl acetate.
[0017] In accordance with another aspect, there is provided a
method of making a switching material, comprising providing a first
part comprising one or more than one polymers, salt, an optional
compound having photochromic and electrochromic aspects, and a
first portion of the solvent portion; providing a second part
comprising an optional hardener, a crosslinking agent and a second
portion of the solvent portion; providing a third part comprising
an accelerant and an optional sacrificial solvent; combining the
first part and the second part; and combining the third part with
the combined first and second parts.
[0018] In accordance with another aspect, there is provided a
method of making a switchable film comprising the steps of:
providing a first part comprising one or more polymers, a salt, one
or more compounds having photochromic and electrochromic
properties, and a first portion of the solvent portion; providing a
second part comprising a hardener, a cross-linking agent and a
second portion of the solvent portion; providing a third part
comprising a catalyst and an optional co-solvent; combining the
first part and the second part; combining the third part with the
combined first and second parts to provide a coatable composition;
and applying the composition to a substrate. The step of applying
the composition may be preceded by a step of partially curing the
switching material. The second part may further comprise a second
polymer.
[0019] In another aspect, there is provided a switching material
comprising about 12 to about 15 wt % chromophore; about 65 to about
75 wt % solvent portion; about 1 wt % salt; about 10 to about 13 wt
% polymer; about 0.21 to about 0.42 wt % crosslinker; and about
0.01 to about 0.02 wt % accelerant.
[0020] In another aspect, there is provided a switching material
comprising: about 12 wt % chromophore; about 74 wt % solvent
portion; about 1 wt % salt; about 12 wt % polymer; about 0.21%
crosslinker; about 0.01 wt % accelerant.
[0021] In another aspect, there is provided a composition
comprising: about 2 wt % to about 25 wt % polymer; about 0.1 wt %
to about 5 wt % crosslinking agent; about 0.1 wt % to about 5 wt %
salt; about 50 wt % to about 90 wt % solvent portion; and
optionally about 2% to about 20 wt % of a compound having
electrochromic and photochromic properties.
[0022] The one or more compounds having photochromic and
electrochromic properties may be in a mobile phase of the switching
material. The one or more compounds may be dispersed throughout the
electrolyte or switching material. The one or more compounds may be
covalently linked to a polymer.
[0023] The switching material, or a film or device comprising the
switching material may be heat-laminatable. The switching material,
or a film or device comprising the switching material, may have a
haze of less than about 3% or less than about 2% or less than about
1.5%. The haze may be assessed before, or after
heat-lamination.
[0024] The switching material may demonstrate less than 5%, less
than 10%, less than 15% or less than 20% decrease in darkening
performance after 500 hours, or after 1000 hours, or after 1500
hours, or after 2000 hours of weathering. The switching material
may demonstrate less than 5%, less than 10%, less than 15% or less
than 20% decrease in darkening performance after 1 MJ/m.sup.2, or
after 2 MJ/m.sup.2, or after 3 MJ/m.sup.2, or after 4 MJ/m.sup.2,
or after 5 MJ/m.sup.2, or after 6 MJ/m2 of weathering.
[0025] This summary does not necessarily describe all features.
Other aspects, features and advantages will become apparent to
those of ordinary skill in the art upon review of the following
description of specific embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] These and other features will become more apparent from the
following description in which reference is made to the appended
drawings wherein:
[0027] FIG. 1 shows a bar graph illustrating darkening performance
of solvents demonstrating suitable cyclic voltammetry (CV)
profiles. Experiments were performed in triplicate, and
representative devices are shown. All samples are 5% S109
chromophore in the solvent, sealed in a sintered glass cell (SGC).
Solvents are named along the X axis; time (hours) in a QSUN Xenon
Test Chamber providing 0.68 W/m.sup.2 of UV light at a wavelength
of 340 nm is along the left side Y-axis; cumulative energy exposure
(MJ/m.sup.2) is along the right side Y-axis. Solid bar--90-100% of
baseline dark state; striped bar--85-90% of baseline dark state;
dotted bar 80-85% of baseline dark state. Solid black `cap` at top
of bar indicates device attained <80% of baseline dark state
(removed from Xenon Test Chamber).
[0028] FIG. 2 shows a bar graph illustrating the change in
Yellowness Index (delta YI, or .DELTA.YI) for the same samples of
FIG. 1. Solid bar--delta YI of 0-5 relative to baseline faded
state; striped bar--delta YI of 5-10 relative to baseline faded
state; dotted bar delta YI of 10-15 of baseline faded state. Solid
black "cap" at top of bar indicates device with delta YI>15.
[0029] FIG. 3 shows a bar graph illustrating darkening performance
of selected solvents with 5% 5109 or 5% 5158 chromophore in
solvent, sealed in an SGC. Experiments were performed in
triplicate, and representative devices are shown. Solvents are
named along the X axis; time (hours) in a QSUN Xenon Test Chamber
providing 0.68 W/m.sup.2 of UV light at a wavelength of 340 nm is
along the left side Y-axis; cumulative energy exposure (MJ/m.sup.2)
is along the right side Y-axis. Solid bar--90-100% of baseline dark
state; striped bar--85-90% of baseline dark state; dotted bar
80-85% of baseline dark state. Solid black `cap` at top of bar
indicates device attained <80% of baseline dark state (removed
from Xenon Test Chamber).
[0030] FIG. 4 shows a bar graph illustrating the change in
Yellowness Index (delta YI, or .DELTA.YI) for the same samples of
FIG. 3. Solid bar--delta YI of 0-5 relative to baseline faded
state; striped bar--delta YI of 5-10 relative to baseline faded
state; dotted bar delta YI of 10-15 of baseline faded state. Solid
black "cap" at top of bar indicates device with delta YI>15.
[0031] FIG. 5 shows a bar graph illustrating darkening performance
of various formulations in a sealed device. Experiments were
performed in triplicate, and representative devices are shown.
Solvents are named along the X axis; time (hours) in a QSUN Xenon
Test Chamber providing 0.68 W/m.sup.2 of UV light at a wavelength
of 340 nm is along the left side Y-axis; cumulative energy exposure
(MJ/m.sup.2) is along the right side Y-axis, All formulation
percentages are weight %. Solid bar--90-100% of baseline dark
state; striped bar--85-90% of baseline dark state; dotted bar
80-85% of baseline dark state. Solid black `cap` at top of bar
indicates device attained <80% of baseline dark state (removed
from Xenon Test Chamber). Samples for alpha 6.1f (no salt) 8.1a and
8.1b had not reached a failure point as of the indicated
explosures
[0032] FIG. 6 shows a bar graph illustrating the change in
Yellowness Index (delta YI, or .DELTA.YI) for the same samples of
FIG. 5. Solid bar--delta YI of 0-5 relative to baseline faded
state; striped bar--delta YI of 5-10 relative to baseline faded
state; dotted bar delta YI of 10-15 of baseline faded state. Solid
black "cap" at top of bar indicates device with delta YI>15.
DESCRIPTION
[0033] There is provided, in part, a switching material comprising
a polymer, a salt and one or more compounds having electrochromic
and photochromic properties.
[0034] Materials with controllable alteration of light transmission
(switching, or switchable materials, compositions, formulations or
the like) according to various embodiments, may be useful in
devices or applications where an optical filter is desired. The
compositions may be used as films or coatings that may be applied
to a surface such as plastic, glass, a window, a lens or the like,
and modify the light transmittance of the surface. Examples of such
devices include optical filters, windows, films, opthalmic lenses,
actinometers, molecular sensors, photochromic inks, paints or
fibers, variable transmission filters, optical information storage
systems, optoelectronic systems, reversible holographic systems,
molecular switches such as those used in molecule-based wires and
circuitry or the like.
[0035] In some embodiments, the switching material may be disposed
upon a first substrate, or "sandwiched` between a first substrate
and a second substrate, the switching material capable of
transitioning between a light state and a dark state based on
application of light in the UV and/or VIS range, and application of
an electric voltage. The substrate may be conductive, or comprise a
conductive coating or surface that may contact the switching
material. Switching material disposed upon a substrate and in
contact with a conductive coating or surface, with or without a
second substrate, may be generally referred to an optical filter.
The switching material may be a liquid, a gel, a solid or a
semi-solid, and may be formed in a layer (coating) with a thickness
of about 0.1 micron (micrometer, .mu.m) to about 100 microns, or
any amount or range therebetween, for example from about 10 microns
to about 50 microns, or from about 0.1 micron to about 10 microns,
or from about 0.5 micron to about 5 microns, or any amount or range
therebetween. In some embodiments, the layer of switching material
may be of uniform, or substantially uniform thickness, or
non-uniform thickness.
[0036] There is further provided, in part, a switchable film
comprising a first, and optionally a second, substantially
transparent substrate, a first and a second electrode disposed on
the surface of at least one of the substrates, and a switching
material disposed between the first and the second substrates and
in contact with the first and the second electrodes. A switching
material may comprise one or more polymers, a solvent portion
comprising one or more solvents, a salt, and a compound having
electrochromic and photochromic properties.
[0037] A switchable film, or optical filter or device comprising a
switchable film, may have a switching time from a dark state to a
faded state of from about 10 seconds to about 5 minutes, or any
amount or range therebetween. Switching time may be altered by
varying one or more of thickness of material (e.g. a layer or cast
sheet of switching material), solvent proportion, chromophore
proportion, degree of crosslinking of the polymer, proportion of
polymer, composition of polymer, hardness of the cross-linked
switching material, or the like. The switchable film may be
optically clear.
[0038] There is further provided, in part, a composition comprising
a polymer, a salt and optionally, one or more compounds having
electrochromic and photochromic properties. The composition may be
substantially non-flowing at a first temperature range (e.g. below
about 25.degree. C. to 30.degree. C.). When heated to a second
temperature range above the first temperature (e.g. from about
50.degree. C. to about 80.degree. C.), the composition may be of a
coatable viscosity. A composition of a coatable viscosity may have
sufficient surface tension or adhesion to be coatable in a layer of
about 0.5 to about 4 mil on a moving web for roll-to-roll
processing. The composition may be extrudable through a die onto a
substrate, a moving web, or into a mold. The die may be a heated
die, heated to about the second temperature range. Following
coating, the composition cools to ambient temperature, or
substantially ambient temperature. The composition may be thermally
cross-linkable at a temperature above, or within the second
temperature range (a curing temperature, or a curing temperature
range).
[0039] There is further provided, in part, a composition comprising
a polymer, a salt, a sacrificial solvent and optionally one or more
compounds having electrochromic and photochromic properties. The
composition comprising the sacrificial solvent is of a coatable
viscosity within a first temperature range.
[0040] In some embodiments, the composition may comprise a polymer
that is crosslinkable. The polymer may be a polyol. The
composition, when crosslinked, may be referred to as a thermoset,
thermoset composition, or thermosettable composition (if
crosslinking has not been initiated, or is partial).
[0041] Generally (and without wishing to be bound by theory), a
thermoset material may exhibit three phases in the curing
process--viscous liquid, gel and solid, each with its own thermal
mechanical properties. At a gel stage (gel point), covalent bonds
connect across the material to provide a 3-dimensional network. At
a gel state, the material may, if cut or strained, demonstrate
stringiness or thinning of the web as it is stretched. As the
thermoset material continues to cure, the cross-linking, if
sufficiently dense, and allowed to continue to a `solid` phase, may
hinder molecular motion.
[0042] For switching materials according to various embodiments,
the matrix of the cured material may be sufficiently open so as to
permit movement of molecules within the matrix, allowing for the
switch between open and closed ring isomers of hybrid
photochromic/electrochromic (hybrid P/E) compounds within the
material. A greater solvent portion than would conventionally be
used to provide a free-standing film may be present.
[0043] There is further provided, in part, a method of making a
switchable film comprising a switching material, comprising
preparing a switching material comprising a polymer, a salt and one
or more compounds having electrochromic and photochromic
properties, coating a layer of the switching material onto a first
substrate and laminating a second substrate to the layer of the
composition. Where the composition further comprises a sacrificial
solvent, the step of laminating the second substrate may be
preceded by a step of removing the sacrificial solvent. The
sacrificial solvent may be removed by vaporization--blown air,
heat, a partial vacuum or a combination thereof. The step of
coating may comprise a step of applying a layer of the composition
onto the substrate; the substrate may be a moving web. The step of
laminating may be followed by a step of curing the switchable
material.
[0044] The terms lamination, to laminate, or the act of lamination
refers generally to the manufacture of an apparatus or material in
multiple layers, providing a composite with improved strength,
stability or other properties. In some embodiments, the layers may
be fixed by adhesive properties of an intermediate layer (e.g. a
layer of switching material between first and second substrates).
In some embodiments, a `sandwich` of switching material between
first and second substrates may be laminated between lites (panes)
of glass (curved or flat) with one or more layers of a
thermoplastic adhesive with the application of heat, or heat and
pressure (e.g. in an autoclave or a press), or heat with reduced
pressure (e.g. in a vacuum bag). Examples of thermoplastic
adhesives include polyvinyl butyral, ethylvinyl acetate or
polyurethane. Lamination involving the application of heat to melt
an adhesive layer may be referred to as `heat` lamination. Heat
lamination may involve application of additional pressure, or
reduced pressure. Heat lamination may be carried out at
temperatures of from about 70.degree. C. to about 150.degree. C. or
any amount or range therebetween, for time periods of from a few
minutes (from about 10 to about 60 minutes) to a few hours. In some
embodiments, heat lamination may be carried out at a temperature of
at least about 90.degree. C., or at least about 100.degree. C., or
at least about 110.degree. C. or at least about 120.degree. C. or
at least about 130.degree. C.
[0045] Switching Material:
[0046] A "switching material", as referenced herein, is a material
that has both electrochromic and photochromic properties. A
switching material may darken (e.g. reach a `dark state`) when
exposed to ultraviolet (UV) light or blue light from a light
source, and may lighten ("fade", achieve a `light state") when
exposed to an electric charge. Such a switching material may be
alternately described as an auto-darkening material. In some
embodiments, the switching material may fade upon exposure to
selected wavelengths of visible (VIS) light ("photofade",
"photobleach"), without sacrifice of the ability to be electrofaded
when restored to a darkened state. In some embodiments, the
switching material may darken when exposed to light comprising
wavelengths from about 350 nm to about 475 nm, or any amount or
range therebetween, and may lighten when a voltage is applied, or
when exposed to light comprising wavelengths from about 500 to
about 700 nm. The switching material may be optically clear.
[0047] The switching material may be a thermoplastic, thermosetting
(uncured) or thermoset (cured) material. The switching material may
be a viscoelastic material (an "elastomer"). Where the switching
material is a thermoset material, it may be cured by heating,
exposure to UV light, chemical reaction, irradiation, electron beam
processing or a combination thereof.
[0048] Materials, compounds, compositions, formulations or the
like, according to various embodiments may be described with
reference to one or more properties, for example, photostationary
state, photostability, visible light transmission (VLT), luminous
transmittance (LT.sub.A), contrast ratio, colour, solubility,
electrochemical durability, thermal stability, switching voltage,
switching time, manufacturability, switching kinetics, haze,
operating temperature, manufacturing conditions or processes or the
like. The one or more properties may be in reference to a compound,
or in reference to a particular material, formulation, composition
or component of a material, formulation or composition.
[0049] Components of a switching material, or a composition for
making a switching material according to various embodiments
include one or more of a crosslinkable polymer, a polymer, an salt,
a cross-linker, a hardener, a hybrid P/E compound, an accelerant
(catalyst), or a co-solvent.
[0050] Coatability refers to the ability to apply the composition
on a moving web. Coordinating dynamic viscosity of the composition
and rate of web travel is within the ability of one skilled in the
art. Generally, a more viscous composition may be applied to a
slower moving web, while a less viscous composition may be applied
to a faster moving web. Thickness of the coating may also be
coordinated by manipulation of composition viscosity and/or rate of
web travel; a more viscous composition applied to a slower moving
web may have a greater thickness than a less viscous composition
applied to a slower moving web.
[0051] Viscosity may be manipulated by the proportion of one or
more of the components of the coatable formulation, including
cross-linkable polymer, rheology modifier, solvent, chromophore,
and/or an optional sacrificial solvent. Viscosity of a coatable
formulation may be manipulated by temperature; a reduction of
temperature may increase viscosity, while an increase in
temperature may decrease viscosity.
[0052] The level of crosslinking may be selected so as to be
sufficiently high to provide a suitable viscosity of the
composition at the desired temperature, but not so high as to form
a gel matrix too solid to hinder molecular motion, and adversely
affect fading kinetics. Degree of crosslinking may affect one or
more of the pot life of the composition, cure rate or hardness of
the resulting crosslinked polymer material, and/or switching
kinetics of the crosslinked switching material. The specific
concentration of cross-linking agent and polymer may vary with the
nature of the crosslinking agent (two, three or more reactive
groups), nature of the polymer (molecular weight, quantity of
reactive --OH groups or the like), presence of formulation
components that may compete with reactive --OH groups and/or
reactive groups of the crosslinking agent, or the like.
[0053] When dissolved in the solvent phase, the ionic components of
the salt separate, and will migrate to the electrodes to form an
electrical double-layer at the electrode/electrolyte interface when
electricity is applied. Separation of the ionic components is
influenced, in part, on the electrochemical environment in the
switching material, which is established, in part, by the
solvent(s) and salt(s) present. A salt with a higher dissociation
constant will generally separate more readily than one with a lower
dissociation constant, and a solvent phase with a higher dielectric
constant, or comprising components with high dielectric constants,
may facilitate this dissociation. More efficient formation of the
electrical double-layer may provide for faster electrochemical
fading of a switching material.
[0054] Photostability may also be affected by the components in a
switching material. Individual components, alone or in combination,
may have varying degrees of photostability (resistance to
degradation--when exposed to light over prolonged periods of time).
As some switching materials may be operated by exposure to UV light
to darken, it may be advantageous so select switching material, or
switching material components, that demonstrate better
photostability. Further, some components may individually have
suitable photostability when exposed to light, but the degradation
becomes readily apparent when combined with one or more components.
As an example, candidate solvents may be combined with chromophore,
or chromophore and salt, and weathered. The samples may be assessed
for photostability by periodic testing of the switching performance
of the sample--darkening when exposed to UV light and fading when
exposed to a portion of visible light (e.g. 500-700 nm, or light
from a low pressure sodium lamp). FIGS. 1 and 2 illustrate the
relative photostability of some solvent-chromophore samples with
weathering; other switching material components may be individually
or collectively screened in a similar manner.
[0055] A formulation may be selected depending on the performance
criteria that may be desired--in some cases a formulation may be
selected to achieve a balance between photostability and
electrofading speed, for example, or may be selected to emphasize
one over the other, depending on the intended use.
[0056] In some embodiments, a higher MW polymer may be useful,
forming a smaller overall portion of the formulation (by wt). In
some embodiments, a lower portion of crosslinking agent may provide
for a less-crosslinked material; a less-crosslinked material may
provide greater mobility in the electrolyte, and greater mobility
of chromophores; greater mobility of switching material components
(e.g. ions, chromophore) may provide for faster electrofading time.
In some embodiments, increasing the solvent portion of a switching
material may decrease fading time. In some embodiments, increasing
a chromophore portion may increase contrast ratio between dark and
faded states. In some embodiments, a BF4 anion as part of the
electrolyte may improve photostability. In some embodiments, a TFSI
anion as part of the electrolyte may decrease fading time. In some
embodiments, increasing a crosslinker portion, polymer portion, or
both a crosslinker portion and a polymer portion, may increase
firmness of a switching material (e.g. cured as a film). In some
embodiments increasing firmness of a switching material may reduce
flow during cure. In some embodiments, an increase in the
proportion of --OH groups on a polymer may increase the amount of
crosslinking. In some embodiments, inclusion of a salt with a
higher dissociation constant in the electrolyte (e.g. TFSI anion vs
BF.sub.4 anion) may decrease fading time. In some embodiments,
increasing the permittivity of the solvent phase by inclusion of a
solvent component with a higher dielectric constant may decrease
fading time; the solvent component with a higher dielectric
constant may have a dielectric constant of from about 5 to about 15
or greater, or any amount or range therebetween, or from about 5 or
greater, or from about 10 or greater, or from about 15 or
greater.
[0057] Polymer:
[0058] A `polymer` ("polymer resin", "resin") generally refers to a
polymer or prepolymer, or mixture comprising a polymer or
prepolymer, with reactive groups that may crosslink
intramolecularly or intermolecularly. A switching material
according may comprise one, or more than one polymers; the
switching material may be thermoplastic, or thermoset, or a
combination of the two (e.g. partially cured). A polymer may
comprise a homopolymer or a copolymer; the copolymer may be a
random, block, alternating, or periodic copolymer, or the like. A
polymer may comprise a linear, branched, or dendrimeric polymer. A
polymer may have any pendant group suitable for crosslinking; in
some embodiments, the polymer is a polyol. Examples of polymers
comprising pendant --OH groups (polyols) include ethylene vinyl
alcohol copolymer, polyvinyl alcohol (PVOH, PVA1), polyvinyl
acetals, glycerol propoxylate-block-ethoxylate, poly(ethylene
oxide) (PEO), partially hydrolyzed ethylene vinyl acetate (EVA),
some fluoropolymers (e.g. those described in WO2011/121078) or the
like. The polymer, or polyol, may be soluble in a solvent portion
of a switching material. Generally, a polyol combined with a
crosslinking agent under suitable reaction conditions may crosslink
two alcohol groups; crosslinking may be inter- or intra-molecular.
A polymer comprising a higher proportion of --OH groups (e.g. %
alcohol subunits) may exhibit a greater degree of cross-linking
than a polymer having a lesser proportion of --OH content. A
polymer of a higher molecular weight may be used in lesser
proportion than a polymer of a lower molecular weight, to achieve a
similar viscosity and/or thickness of switchable material. Thus,
selection of a higher molecular weight polymer, which may be used
in a lesser proportion than a polymer of similar composition (%
--OH groups) in a switching material; use of a lesser proportion of
polymer (and/or other component) may allow for a greater proportion
of solvent or ionic medium, or other components, thereby providing
a means for manipulation of switching speed, light transmission in
faded or dark states, pot life, suitability for different coating,
mixing, use or storage applications or the like. As an example, a
greater proportion of solvent, or ionic species, or both, in the
switching material, may increase switching speed.
[0059] Polyvinyl acetal may be produced by reacting polyvinyl
alcohol and one or more aldehyde species, according to known
methods. The polyvinyl alcohol may be of any suitable molecular
weight range to provide the desired molecular weight range of the
polyvinyl acetal polymer. The aldehyde used for the production of
the polyvinyl acetal is not particularly limited, and may include
formaldehyde (including paraformaldehyde), acetaldehyde (including
paraacetaldehyde), propanal, propionaldehyde, butyraldehyde,
n-octyl aldehyde, amyl aldehyde, hexyl aldehyde, heptyl aldehyde,
2-ethylhexyl aldehyde, cyclohexyl aldehyde, furfural, glyoxal,
glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde,
3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde,
m-hydroxybenzaldehyde, phenylacetaldehyde,
beta-phenylpropionaldehyde or the like. The aldehyde may be used
singly, or two or more may be used in combination. In some
embodiments, the aldehyde is butyraldehyde, and the polymer is
polyvinyl butyral (PVB).
[0060] PVB is a random copolymer, and methods for preparation of
PVB are known in the art. PVB may be described with reference to
one or more of molecular weight (MW), percent alcohol groups
(percent polyvinyl alcohol content), degree of acetalization
(percent polyvinyl acetate content) or the like. Varying one or
more of these provides for PVB with varying properties. Some PVBs
may have a polyvinyl alcohol content of from about 5% to about 30%,
or about 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, 26, 27, 28, 29 or 30%, or any amount or range
therebetween. Some PVB may have a polyvinyl acetate content of from
about 0.1% to about 10%, or about 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4,
4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10% or any amount or
range therebetween.
[0061] Molecular weight (average) in g/mol of PVB may be determined
by any of several methods known in the art, for example phase
gradient polymer elution chromatography. Some PVB (before
crosslinking) may have an average molecular weight from about 20000
g/mol (20K) to about 350000 g/mol (350K), or any amount or range
therebetween, or about 30000 g/mol (30K), about 40000 g/mol (40K),
about 50000 g/mol (50K), about 60000 g/mol (60K), about 70000 g/mol
(70K), about 80000 g/mol (80K), about 90000 g/mol (90K), about
100000 g/mol (100K), about 125000 g/mol (125K), about 150000 g/mol
(150K), about 175000 g/mol (175K), about 200000 g/mol (200K), about
225000 g/mol (225K), or about 250000 g/mol (250K), or about 300000
g/mol (300K), or about 325000 g/mol (325K), or any amount or range
therebetween. One or more polymers, or one or more PVBs may be
present in a composition or formulation, independently, in an
amount of about 0.5 wt % to about 25 wt %, or any amount or range
therebetween, for example 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 or 24 wt %. Some PVB
resins may have an --OH group content of from about 18 to about
21%, and/or an acetal content of about 1-2%, and/or an MW of from
about 50K to about 350K. Examples of PVB resins that may be used in
compositions or formulations are set out in Table 1, below. In some
embodiments two or more types of PVB may be combined in a film. Two
or more polymers, including one or more types of PVB, to be
combined may be selected for solubility in a solvent, or solvent
mixture, or where their combination provides for an improved or
unexpected property such as resistance to flow, improved switching
speed (when combined in a switchable film), adhesion to substrate,
retention of solvent or the like.
[0062] Cross-Linker:
[0063] in some embodiments, the one or more polymers, or one or
more polyols may be crosslinked. A cross-linker (cross-linking
agent) may comprise two or more reactive groups; reactive groups
may independently be, for example, aldehyde, epoxide, isocyanate,
silane or the like. A crosslinking agent may be soluble in a
solvent portion of a switching material. Examples of crosslinking
agents include aldehyde, isocyanate, melamines, phenolic resins or
the like. A hardener may be used with some crosslinking agents.
Examples of aldehyde crosslinkers include terephthalaldehyde and
the like. Examples of epoxides include diglycidyl ethers of
polypropylene glycol (e.g. DER736, DER732, both from Dow Chemical),
bisphenol A diglycidyl ether (BADGE), 1,4-butanediol diglycidyl
ether, 1,4-cyclohexanedimethanol diglycidyl ether,
1,2,5,6-diepoxycyclooctane, resorcinol diglycidyl ether,
tris(4-hydroxyphenyl)methane triglycidyl ether or diglycidyl
1,2-cyclohexanedicarboxylate and the like. Examples of isocyanate
crosslinking agents include aromatic and aliphatic diisocyanates;
examples of aliphatic diisocyanates include hexamethylene
diisocyanate (HMDI), dimers, trimmers, or multimers of HMDI (e.g.
DESMODUR.TM. N100, N3300A, N3600 from Bayer), isophorone
diisocyanate, methylene dicyclohexyl diisocyanate, xylylene
diisocyanate, cyclohexane diisocyanate, tetramethyl xylylene
diisocyanate, isopropenyl dimethylbenzyl isocyanate,
trimethylhexamethylene diisocyanate, norbornane diisocyanate or the
like. Examples of aromatic diisocyanates include diphenylmethane
diisocyante, toluene diisocyanate, p-phenylene diisocyanate,
naphthalene diisocyanate or the like. The isocyanate crosslinking
agent may be a blocked isocyanate, e.g. a malonate, triazole,
caprolactam, sulfite, phenol, keotoxime, pyrazole or alcohol
blocked isocyanate. A blocked isocyanate may be advantageous in
some embodiments, as it may remain unreactive with other components
of the formulation until `unblocking`--unblocking of the blocked
isocyanate may be performed, for example, by heating the
formulation. The cross linker may be present in a composition or
formulation in an amount of about 0.01% to about 10%, or any amount
or range therebetween, for example 0.02, 0.04, 0.06, 0.08, 0.1,
0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, or 9 wt %.
[0064] Hardeners:
[0065] An epoxide crosslinking agent may be used in combination
with a hardener. A hardener ("curing agent") may be an anhydride,
for example MHHPA (methylhexahydrophthalic anhydride) THPA
(tetrahydrophthalic anhydride), MTHPA (methyltetrahydrophthalic
anhydride), HHPA (hexahydrophthalic anhydride), 4-MHHPA or the
like. A hardener may be soluble in a solvent portion of the
switching material. A hardener may be present in a composition or
formulation in an amount of about 0.5% to about 10%, or any amount
or range therebetween, for example 1, 2, 3, 4, 5, 6, 7, 8, or 9 wt
%.
[0066] Accelerant:
[0067] An accelerant may alternately be referred to as a
`catalyst`. In some embodiments, an accelerant may be a Lewis acid
or a Bronstead acid. In some embodiments, an accelerant may
comprise a transition metal. In some embodiments, an accelerant may
comprise an organometallic complex, wherein the metal component is
a transition metal. Examples of transition metals may include Mn,
Sn, V, Bi, Zn, Co, Zr, Al, Cr, Ti, or Cu, or the like. An
accelerant may be soluble in a solvent portion of a switching
material. Examples of accelerants that may be used with materials
comprising an epoxide reactive group may include AMC-2 (chromium
2-ethylhexanoate in Palatinol 711P), ATC-3 (AMPAC Fine Chemicals),
zinc 2-ethyl hexanoate (99%, or 80% in mineral spirits), AC8
(Available from Broadview), CXC1612 or CXC1613 (King Industries),
1,4-diazabicyclo[2.2.2]octane (DABCO), HCl, p-toluenesulfonic acid,
potassium t-butoxide, Tyzor ZEC (Dorf-Ketal), Tyzor AA75
(Dorf-Ketal), titanium tetraisopropoxide, copper (II) chloride.
Examples of accelerants that may be used with materials comprising
an isocyanate reactive group may include dibutyltin dilaurate,
dibutyltin diacetate, dibutyltin oxide, transition metal complexes
of acetylacetonates, octanoates, metal chelates or the like. A pot
life extender (e.g. 2,4 pentanedione or "PD") may be included in a
composition with the accelerant. Where the crosslinker is an
aldehyde, the accelerant may be a Bronstead acid, or a Lewis acid.
Examples include HCl, p-toluenesulfonic acid, methanesulfonic acid,
p-toluenesulfonic acid: pyridine complex, N-bromosuccinimide, iron
trichloride, ammonium triflate,
1,3-Bis[3,5-bis(trifluoromethyl)phenyl]thiourea,
1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea with mandelic acid,
sulfuric acid, trifluoroacetic acid, titanium tetraisopropoxide,
zinc chloride, acetic acid, chloroacetic acid, phosphoric acid,
maleic acid, oxalic acid, p-toluenesulfonic acid:DBU complex,
ammonium nitrate. In some embodiments, the acid may be selected
from a group comprising HCl, p-toluenesulfonic acid,
methanesulfonic acid, p-toluenesulfonic acid:pyridine complex,
N-bromosuccinimide, iron trichloride, ammonium triflate,
1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea,
1,3-bis[3,5-bis(trifluoromethyl)phenyl]thiourea with mandelic acid,
and sulfuric acid. An accelerant may be present in a switching
material, composition or formulation in an amount of about 0.001%
to about 1%, or any amount or range therebetween, for example,
0.002, 0.005, 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or
0.9 wt %.
[0068] Other Polymers:
[0069] In some embodiments, the switching material, composition or
formulation may further comprise one or more additional polymers,
the one or more additional polymers may be crosslinkable or may not
be crosslinkable. The one or more additional polymers may be a
rheology modifier. The one or more additional polymers may be
soluble in a solvent portion of a switching material. Examples of
second polymers include poly(methyl methacrylate) (PMMA), nitrile
butadiene rubber (NBR), polyvinylpyrrolidone (PVP), polyvinylidene
fluoride (PVDF), poly(dimethylsiloxane) (PDMS), poly(ethyl
methacrylate) (PEMA), hydroxypropyl cellulose, PEG-DMA
(poly(ethylene glycol) dimethacrylate), PHEMA (poly(2-hydroxyethyl
methacrylate), Plexiglas' G-UVT acrylic, polychloroprene,
polybutadiene, PDMS-g-PEG (PEG-modified PDMS), PEO (polyethylene
oxide), PEG-MEMA (PEG-methylether methacrylate), silicones, PDMS,
PPGMA (poly(propylene glycol), EGDMA (ethylene glycol
dimethacrylate), PVDC (polyvinylidene chloride), PVC
(polychlorovinyl), PVDC-PVC, cyclo olefin copolymer (COC)
(APEL.TM.), carboxymethyl cellulose (CMC), SOLEF.TM. 21520,
SOLEF.TM. 21508, zein, polyisobytulene-600,
poly(ethylene-co-methacrylic acid (SURLYN.TM. 60),
polyethylene-co-(ethylacrylate), ethylacrylate, poly(vinylidene
chloride-co-vinyl chloride), polyisoprene, polybutene, poly(sodium
4-styrene sulfonate), HEMA (hydroxyethyl)methacrylate or
combinations thereof, or copolymers thereof. Examples of sol-gels
include silicon-oxygen based sol-gels, aluminum-oxide based
sol-gels, titanium-oxide sol-gels or combinations thereof. In some
embodiments, the one or more polymers or sol-gels may be present in
an amount from about 0.1% to about 10% (by weight) or any amount or
range therebetween, for example 1, 2, 3, 4, 5, 6, 7, 8, or 9%, or
any amount or range therebetween. In some embodiments the one or
more polymers or sol-gels may function as a rheology modifier.
Inclusion of a rheology modifier may increase viscosity of a
formulation in an uncured or partially cured state, and may
facilitate handling of the composition (e.g. allow or improve
coating of a moving web, allow or improve molding of the
composition).
[0070] Switchable Compound:
[0071] in some embodiments, the switchable compound may comprise,
photochromic properties, electrochromic properties, or both
photochromic and electrochromic properties. In some embodiments,
the transition of the switchable material between dark and faded
states may be temperature independent. In some embodiments the
switchable compound darkens (visible light transmission decreases)
when exposed to light comprising wavelengths of about 420 nm or
less (including UV light, and some short-wavelength visible light),
and fades (visible light transmission increases) when an electric
potential is applied across first and second electrodes and/or when
exposed to light of from about 500 to about 750 nm. The switchable
compound may additionally fade when exposed to light of about
500-550 nm. A switchable compound may be soluble in a solvent
portion of a switching material. In some embodiments, the
switchable compound may be a switchable plasticizer. Without
wishing to be bound by theory, the switchable compound may embed
within the polymer matrix and increase the free volume of the
polymer; this may provide a reduced glass transition temperature,
reduced brittleness, increased flexibility and/or increased
durability. In some embodiments, increasing concentration of
switchable compound may decrease the viscosity of the polymer
matrix. In some embodiments, the hardness of the layer may decrease
with increasing concentration of switchable compound in the layer.
In some embodiments, the switchable compound may also be suitable
for transport of charge within the interlayer. Examples of such
switchable compounds include hybrid photochromic/electrochromic
(hybrid P/E or P/E) compounds. Hybrid P/E compounds are generally
organic, and include hexatrienes, diarylethenes,
dithienylcyclopentenes and fulgides. Oxidation of the hybrid P/E
compound to interconvert between a ring-closed and a ring-opened
form may be induced by application of a voltage to a switchable
material comprising the compound, and may be independent of the
polarity of the applied voltage. In some embodiments, the hybrid
P/E compound may be an anodic species, that is, the electrochromic
colour change (electrochromic fading, electrochromic transition
from a dark state to a light state) occurs primarily at the anode
of an electrochromic film or device. In other embodiments, the
hybrid P/E compound may be a cathodic species, where the
electrochromic color change occurs at the cathode of an
electrochromic film or device.
[0072] The hybrid P/E compounds may be compounds according to
Formula I, inclusive of A and B isomers. The compounds each
comprise two or more isomers, including ring-open, or open, isomers
(Isomer A) and ring-closed, or closed, isomers (Isomer B). These
compounds are reversibly convertible between open and closed forms.
When used herein, a numeral or alpha-numeric reference (with suffix
`A`) denotes the ring-open isomer of a compound, and a primed
numeral or alpha-numeric reference (with suffix `B`) denotes the
ring-closed isomer of the same compound.
[0073] Compounds according to various embodiments of the invention
may undergo catalytic electrochemical oxidation. The
electrochemical conditions may be catalytic conditions, and
compounds according to various embodiments of the invention may
undergo catalytic electrochemical oxidation. Catalytic
electrochromism of selected diarylethenes has been demonstrated and
is described in U.S. Pat. No. 7,777,050. The electrochemical
conditions may be catalytic conditions and methods of switchable,
or operating, a switchable material from a dark to a faded state
may employ application of a catalytic electric charge. A catalytic
amount of an electric charge may be positive or negative, and may
be from about 0 to about 5 volts, or any amount or range
therebetween. One or more hybrid P/E compounds according to various
embodiments of the invention may be present in a switchable
material in an amount (% weight) of about 0.05% to about 30%, or
any amount or range therebetween, for example about 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23
24, 25, 26, 27, 28 or 29%.
[0074] Examples of diarylethene compounds are described in U.S.
Pat. No. 7,777,055, WO2010/142019 and PCT/CA2012/000910, all of
which are incorporated herein by reference.
[0075] Examples include 1,2 diaryl cyclopentene compounds
reversibly convertible between Formula 1A (ring-open isomer) and
Formula 1B (ring-closed isomer) of Scheme 1 or Formula VIIA and
VIIB of Scheme 23:
##STR00001##
wherein
[0076] Z is N, O or S;
[0077] Each R.sub.1 is .sub.independently selected from the group
consisting of H, halo;
[0078] Halo is F, Cl, Br, I;
[0079] Each R.sub.2 is .sub.independently selected from the group
consisting of H, halo, a polymer backbone, alkyl or aryl; or, when
both R.sub.2 together form --CH.dbd.CH-- and form part of a polymer
backbone;
[0080] Each R.sub.3 is .sub.independently selected from the group
consisting of H, halo, CO.sub.2Y, alkyl, alkoxy, thioalkyl,
##STR00002##
or aryl, and Y is independently selected from the group comprising
H, a metal, alkyl, aryl, --(O--CH.sub.2CH.sub.2).sub.4--H, or
##STR00003##
[0081] Each R.sub.4 is independently selected from the group
consisting of
##STR00004##
or aryl;
[0082] Each R.sub.5 is independently selected from the group
consisting of H, halo, alkyl, alkoxy, thioalkyl or aryl; and
X.dbd.N, O or S.
[0083] In another embodiment, R.sub.3 and R.sub.5 are --CH.dbd.CH--
and joined to form an unsaturated ring, providing a compound
reversibly convertible between Formula VIIA (ring-open isomer) and
Formula VIIB (ring-closed isomer) of Scheme 2:
##STR00005##
wherein;
[0084] Z is N, O or S;
[0085] Each R.sub.1 is .sub.independently selected from the group
consisting of H, halo;
[0086] Each R.sub.2 is .sub.independently selected from the group
consisting of H, halo, a polymer backbone, alkyl or aryl; or, when
both R.sub.2 together form --CH.dbd.CH-- and form part of a polymer
backbone.
[0087] Each R.sub.6a, R.sub.6b, and R.sub.6c; R.sub.7a, R.sub.7b
and R.sub.7c; R.sub.8a, R.sub.8b, R.sub.8c R.sub.8d and R.sub.8e;
R.sub.9a, R.sub.9b, R.sub.9c, R.sub.9d and R.sub.9e; R.sub.10a,
R.sub.10b, R.sub.10c and R.sub.10d may be independently selected
from the group consisting of H, halo, --OH, alkyl, alkoxy, ether,
silyl, thioalkyl, aryl or CO.sub.2Y, and Y is as referenced herein.
Alkyl may be from 1 to 10 carbons, linear or branched. Aryl may be
phenyl, thiophene, substituted phenyl, substituted thiophene. Each
of the substituted aryls may be substituted in the 1, 2, 3, 4, or 5
position by an alkyl, ether, --OH, halo,
[0088] Examples of hybrid P/E compounds include:
##STR00006## ##STR00007##
[0089] Solvent Portion:
[0090] An electrolyte component of a switching material may
comprise a solvent portion. The solvent portion may comprise one or
more solvents, the one or more solvents may alternately be referred
to as plasticizers. In some embodiments, the solvent may have one
or more of the following characteristics: a boiling point of about
150.degree. C. or greater, a vapour pressure of about 0.001 mmHg or
less at 20.degree. C., a Yellowness Index (YI) of about 6 or less;
a flash point of about 80.degree. C. or greater, a melting point of
about 40.degree. C. or less. The one or more solvents may be a
plasticizer, or act as a plasticizer. In some embodiments, the one
or more solvents may have a low dielectric constant. In some
embodiments the one or more solvents has a dielectric constant of 5
or greater, or of about 10 or greater, or of about 15 or
greater.
[0091] In some embodiments, the one or more solvents, when combined
with chromophore (5 wt %) demonstrates suitable photostability,
shown by darkening performance of 90-100% of baseline for at least
250 hours of weathering, exposed to a light source providing 0.68
W/m.sup.2 of UV light at a wavelength of 340 nm--or about 0.6
MJ/m.sup.2 cumulative exposure). In other embodiments, the one or
more solvents demonstrates suitable photostability for at least
300, 400 or 500 hours of weathering.
[0092] The one or more solvents may be selected to avoid HCN or HCl
degradation products (e.g. when tested for photostability under
natural or simulated sunlight) and/or avoid one or more of NH
(amino) functional groups, aromatic groups, or primary alcohol
groups. In some embodiments, the solvent does not contain water, or
does not contain more than 2% water.
[0093] Examples of solvents include triglyme, tetraglyme, propylene
carbonate, ethylene carbonate, 1,2-butylene carbonate (BC),
delta-valerolactone, formamide, 3-methyl-2-oxazolidone, phthalide,
tetramethylurea, butyrolactone, cyclopentanone, ethylene glycol
phenyl ether; diethylene glycol monobutyl ether; diethyl succinate;
dimethylglutarate; N-methylpyrrolidone (NMP) ethyl myristate;
mineral seal oil; diethylene glycol n-butyl ether acetate; Eastman
C11 ketone; diisobutyl adipate; dihexyl azelate; diethyl maleate;
diisooctyl azelate; triethylene glycol monobutyl ether
(butoxytriglycol); diisooctyl dodecanedioate;
2-(2-ethylhexyloxy)ethanol; glyceryl triacetate; tetramethylene
sulfoxide; dibutyl adipate; 3-dodecylheptamethyltrisiloxane;
diethyl sebacate; dibutyl itaconate; 1,4-Butanediol; butyl
sulfoxide; diethylene glycol; octyl octanoate; hexyl octanoate;
diisodecyl adipate; diethylene glycol monoethyl ether acetate;
1,3/1,4-cyclohexanedimethanol (CHDM); 1-Decanol;
2-methylglutaronitrile; methyl palmitate; tri(propylene glycol)
butyl ether (Dowanol.TM. TPnB); 1-Dodecanol; tetradecane;
diethylene glycol hexyl ether; dioctyl ether; methyl stearate;
hexyl hexanoate; butyl diglyme; triisopentylamine;
Bis(2-ethylhexyl) sebacate; 1,5-dicyanopentane; diisobutyl
fumarate; 2,2,4-trimethyl-1.3-pentanediol dibenzoate; poly(ethylene
glycol) monolaurate; isooctyl tallate; poly(ethylene glycol)
monooleate; hexaethyldisiloxane; poly(ethylene glycol) dioleate;
triethylene glycol di-2-ethyl butyrate (TEG DEB); tributyrin
(butanoic acid), 1,2,3-propanetriyl ester; tetramethylene sulfone
(sulfolane); polyethylene glycol dimethyl ether m.w. .about.250
(PEG-DME 250); bis(2-ethylhexyl) adipate; tetraethylene glycol;
hexa-decamethylheptasiloxane; dioctyl terephthalate;
Bis[2-(2-butoxyethoxy)ethyl] adipate (BEEA); triethylene glycol
bis(2-ethylhexanoate) (TEG BEH); propylene carbonate (PC);
triethylene glycol monomethyl ether (methoxytriglycol); triethylene
glycol monoethyl ether (ethoxytriglycol); 18-crown-Ether;
1,3-dimethylimidazolidinone (DMI); poly(ethylene glycol)
bis(2-ethylhexanoate); 1,5-pentanediol; di(ethylene glycol)
dibenzoate; 2-ethylhexyl-(s)-lactate; tripropylene glycol;
dipropylene glycol; 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate
("Texanol"); tri(propylene glycol) methyl ether (TPM); di(propylene
glycol) dibenzoate; dipropylene glycol n-butyl ether; diethyl
azelate; dimethyl adipate (DMAd), diethyl adipate (DEAd),
poly(propylene glycol) dibenzoate; propylene glycol phenyl ether;
poly(ethylene glycol) dibenzoate; 2-ethyl-1,3-hexanediol; propylene
glycol diacetate (PGDA), dibutyl itaconate (BI), dimethylglutarate,
diethyl-2-dimethyl glutarate, dimethyl-2-methyl glutarate
(Rhodiasolv IRIS,IRIS, RI); or the like. In some embodiments, the
solvent is optically clear, or substantially optically clear, and
the one or more salt, rheology modifiers, gelling agents, polymers,
co-solvents, accelerants, hardeners, epoxides and other components
of a switching material or composition are soluble in the solvent.
In some embodiments, the solvent is a Lewis base. In some
embodiments, the solvent does not comprise nitrogen. In some
embodiments, the solvent does not include a lactone group, or a
lactam group. Without wishing to be bound by theory, it may be
preferable to avoid lactone- or lactam-containing solvents, as they
may polymerize. In some embodiments, it may be preferable to avoid
solvents with carbon-carbon double bonds, as these molecules may
interact with UV light that maybe used to operate the switching
material.
[0094] The solvent portion of a switching material or composition
may comprise an amount from about 30% to about 95% (by weight), or
any amount or range therebetween, for example 30, 40, 50, 60, 70,
80 or 90%, or any amount or range therebetween.
[0095] Salt:
[0096] A switching material may further comprise a salt. A salt is
generally inert, has a high ionic strength in solution, and
generally comprises a cation and an anion pair. In a solution, a
salt may separate into cation and anion components, forming a
solution in the solvent portion, which may migrate to negative and
positive electrodes in a system where electricity is applied, such
as a switchable film comprising a switching material and first and
second electrodes. In some embodiments a salt may be described
generally as a "supporting electrolyte"; a medium incorporating one
or more salts may be described generally as an "ionic medium". In
some embodiments, the cation, the anion or the cation and the anion
may be an organic cation or an organic anion. Examples of cations
include alkali metal (e.g. Li, Na, K, Cs) ions; examples of organic
cations include tetralkylammonium or tetraalkylphosphonium, where
"alkyl" may be from 1 to 10 carbons (e.g. methyl, ethyl, propyl,
butyl, pentyl, hexyl, phenyl, or the like), for example tetramethyl
ammonium (TMA), tetraethyl ammonium (TEA), tetrabutyl ammonium
(TBA), tetramethyl phosphonium (TMP), tetraethyl phosphonium (TEP),
tetrabutyl phosphonium (TBP), tetraphenyl phosphonium (TPP)
tributylmethylphosphonium (TMP) or the like. Examples of anions
include halide (F, Cl, Br) ions, perchlorate (ClO.sub.4), nitrate
(NO.sub.3), sulfate (SO.sub.4); examples of organic anions include,
tetrafluoroborate (--BF.sub.4), hexafluorophosphate (PF.sub.6),
trifluoromethanesulfonate (TFMS), tetraphenylborate
((C.sub.6H.sub.5).sub.4B; or "BPh.sub.4"),
bis(trifluoromethanesulfonyl)imide (--TFSI), bis(oxotlato)borate
(BOB) ions, or the like
[0097] Examples of salts include NaCl, NaClO.sub.4, NaNO.sub.3,
NaBF.sub.4, NaPF.sub.6, NaTFMS, NaTPB, KCl, KSO.sub.4, KNO.sub.3,
KBF.sub.4, KCF.sub.3SO.sub.3, KClO.sub.4, KPF.sub.6,
KC.sub.6H.sub.54B, CsCl, CsClO.sub.4, Cs.sub.2O.sub.4S, CsNO.sub.3,
CsBF.sub.4, CsF.sub.6P, CsTFMS, CsTPB, TMACl, TMABF.sub.4,
TMANO.sub.3, TMATFMS, TEABF.sub.4, TEAC.sub.1, TEAClO.sub.4,
TEASO.sub.4, TEANO.sub.3, TEAPF.sub.6, TEATFMS, TEABF.sub.4, TBACl,
TBAClO.sub.4, TBABF.sub.4, TBAPF.sub.6, TBABPh.sub.4, TBANO.sub.3,
TBATFMS, TBA-TFSI, TBPBF.sub.4, TBPPF.sub.6, TPBBPh.sub.4, LiTFSI,
triflate, lithium bis(oxatlato)borate (LiBOB), lithium perchlorate
(LiClO.sub.4) or the like. The one or more salts may be present in
an amount from about 0.05% to about 10% (by weight) or any amount
or range therebetween, for example 0.05, 0.1, 0.2, 0.4, 0.6, 0.8,
1, 2, 3, 4, 5, 6, 7, 8, or 9%.
[0098] A solvent portion comprising one or more solvents, together
with one or more salts, may be referred to as an electrolyte, or an
electrolyte portion of the switching material. The electrolyte may
comprise a mobile phase of the switching material and allow
sufficient mobility of the chromophore(s) to facilitate the
oxidative ring opening of chromophores.
[0099] Sacrificial Solvent:
[0100] a sacrificial solvent (co-solvent) may be included in a
composition to confer advantageous or preferred characteristics to
the composition. Such characteristics may include reduced
viscosity, slower polymerization rate, coatability or the like. The
switching material or components thereof, may be soluble in the
sacrificial solvent. A co-solvent is compatible with other
components of the composition. A co-solvent may be selected from a
group comprising toluene, tetrahydrofuran (THF), methyl ethyl
ketone (MEK), ethyl acetate or the like. A composition may comprise
from about 10% to about 75% (by weight) of a co-solvent, or any
amount or range therebetween, for example, 10, 20, 30, 40, 50, 60
or 77%, or any amount or range therebetween. In some embodiments, a
co-solvent may comprise from about 1, to about 1.5, to about 2, to
about 2.5 or to about 3 equivalents in a composition.
[0101] Additionally, switching material or compositions may further
comprise one or more other additives, such as dyes, UV light
stabilizers, antioxidants, surfactants, adhesion promoters, charge
carriers, charge compensators or the like.
[0102] Increasing or decreasing the amount of accelerant,
crosslinking agent or the like may increase or decrease pot-life;
some accelerants may have different reactivity with different
reactive groups, for example, some accelerants may interact more
readily with a primary --OH group compared to a secondary --OH
group, whereas others, may interact more readily with a secondary
--OH or a tertiary --OH group, relative. It may be desirable in
some embodiments to include a blocked isocyanate crosslinking
agent.
[0103] Methods of Preparing Switchable Materials and Coatable
Formulations:
[0104] In some embodiments, components of the switching material
may be combined in particular order, or in particular
subcombinations (`parts`), with the parts combined at a later
point. Preparation of first, second and/or third parts may be
advantageous to solubilize one or more components of a switching
material, prevent side reactions, or to prevent initiation of
crosslinking (`curing`) before the formulation is complete or ready
for casting or coating. Thus, there is further provided, in part, a
method of making a switching material, comprising the steps of:
providing a first part comprising a polymer, an optional hybrid P/E
compound, an salt and a first portion of a solvent; providing a
second part comprising an optional hardener, a crosslinking agent
and a second portion of the solvent; providing an accelerant and an
optional co-solvent; combining the first part and the second part;
and combining the third part with the combined first and second
parts. Where a blocked isocyanate is included, the components of
the coatable switching material may be prepared as a single
mixture, the blocking group preventing crosslinking. Where a
blocked isocyanate is included, a method of preparing a switchable
material may include a step of unblocking (e.g. heating to a
suitable temperature) before curing proceeds.
[0105] The switching material may be coatable (a coatable switching
material or formulation). A coatable switching material is one that
is of suitable viscosity to be applied to a substrate in a suitable
thickness and substantially uniform manner. Viscosity of a
switching material may be altered by increasing or decreasing the
quantity of sacrificial solvent, altering the polymer (different
quantity and/or molecular mass), increasing or decreasing
temperature of the switching material, inclusion of a rheology
modifier or the like. In some embodiments, the switching material
does not include a sacrificial solvent, and viscosity is
manipulated by heating the switching material and/or using a heated
die for coating. Partial curing of the switching material in
advance of, or during the process of coating, may also increase the
viscosity of the switching material applied to a moving web, or
extruded or injected into a mold or extruded or applied onto a
substrate. Curing may be slowed or stopped by decreasing
temperature, and/or diluting the partially cured material with a
co-solvent. Increasing temperature and/or removal of the co-solvent
may subsequently allow curing to proceed to completion. The
switching material may be prepared as a sheet or layer by extrusion
through a sheeting die under pressure; the die may be heated.
[0106] The switching material, or one or more parts thereof may be
treated to remove dissolved gas (oxygen, air, or the like), and/or
treated to remove water, or prepared in an environment with reduced
oxygen and/or reduced humidity. In some embodiments, one or more of
the steps of making a switchable formulation, coating a substrate,
or curing the film may be performed in an inert atmosphere (e.g.
nitrogen, with less than 100 ppm oxygen, less than 100 ppm water,
or both); a reduced humidity atmosphere (e.g. about 5-15% relative
humidity), or in an open atmosphere. In some embodiments, a method
of making a coatable formulation, coating of substrates and/or
curing of a switching material may be performed in a reduced
humidity and/or reduced oxygen environment, for example less than
100 ppm relative humidity, and/or less than 100 ppm oxygen.
[0107] A switching material may be coated at a suitable thickness
onto a conductive coating of a substrate using a slot die, knife
coater, roll-to-roll coating method, extrusion, dipping, spraying,
spin coating, hand-drawing or the like. A suitable coating
thickness may be selected such that the switching material is of
the desired thickness once the co-solvent is evaporated (if a
co-solvent is present), or the final layer is of the desired
thickness following cooling and/or crosslinking of the coated
switching material. For example, to obtain a final thickness of
about 50 microns, a switching material with co-solvent may be
applied to the substrate in a layer of about 100 to about 120
microns. A second layer of substrate is laminated on top of the
coated switching material (conductive side in contact with the
switching material) to form a sandwich structure. The laminated
`sandwich` may be cured, or allowed to continue to cure (if curing
is initiated during the coating or laminating process) and if
desired, cut to a suitable size. Busbars or other electrical
contacts may be added if desired.
[0108] In some embodiments, when the switching material is disposed
upon, or sandwiched between the substrate(s), the switching
material is optically clear before, after or before and after
lamination (e.g. demonstrating a haze of less than about 5%, less
than about 4%, less than about 3%, less than about 2% or less than
about 1%. Haze may be measured using methods known in the art, for
example use of an XL-211 Hazemeter from BYK-Gardner, according to
manufacturer's instructions.
[0109] A second substrate may be laminated on top of the disposed
switching material (with a conductive layer of the second substrate
in contact with the switching material) to provide a switchable
(variable transmittance) optical filter. If desired, the switchable
optical filter may be cut to a desired size or shape, and
electrical contacts (e.g. busbars, wires or the like) may be added,
to facilitate application of a voltage to the switching material.
The step of laminating may be preceded by, or followed by, a step
of crosslinking or curing of the switching material. The step of
curing may comprise heating the switching material to a temperature
suitable for crosslinking (e.g. about 20.degree. C. to about
90.degree. C., or any amount or range therebetween. The step of
disposing may be preceded by a step of filtration of the switching
material.
[0110] In other methods, a switching material, or one or more
components of the switching material, may be formed into pellets,
chips or flakes and mixed with other components of the switching
material, and/or a thermoplastic material (e.g. in a screw mixer)
and extruded through a die to form one or more layers or films. The
mixer, die and/or extruder may be heated. Alternately, the extruded
material may itself be pelletized, for subsequent blending with
other materials and extruded in a second extruder to produce a
switchable film, or molded to produce a switchable article.
[0111] A substrate may be rigid or flexible--an optical filter
comprising one or more flexible substrate(s) may be in the form of
a film that may be applied to a rigid material, such as a pane of a
window, or a lens. A substrate may comprise glass, plastics or
thermoplastic polymers. Examples of glass include float glass,
tempered glass, laminated glass, tinted glass, mirrored glass,
flexible glass (e.g. Willow Glass from Corning), reinforced glass,
chemically-strengthened glass (e.g. alkali-aluminosilicate
glass--GorillaGlass from Corning), monolithic glass, multilayered
glass, safety glass, bullet-resistant glass or "one-way"
bullet-resistance glass. Examples of thermoplastic polymers include
polyesters (PE), polycarbonates, polyamides, polyurethanes,
polyacrylonitriles, polyacrylacids, (e.g. poly(methacrylic acid),
including polyethylene terephthalate (PET), polyolefins (PO) or
copolymers or heteropolymers of any one or more of the above, or
copolymers or blends of any one or more of the above with
poly(siloxane)s, poly(phosphazenes)s, or latex. Examples of
polyesters include homopolymers or copolymers of aliphatic,
semi-aromatic or aromatic monomeric units, for example
polycondensed 4-hydroxybenzoic acid and
6-hydroxynapthalene-2-carboxylic acid (VECTRAN.TM.), polyethylene
napthalate (PEN), polytrimethylene terephthalate (PTT),
polybutylene terephthalate (PBT), polyethylene terephthalate (PET),
polyhydroxyalkanoate (PHA), polyethylene adipate (PEA),
polycaprolactone (PCL) polylactic acid (PLA), polyglycolic acid
(PGA) or the like. Examples of polycarbonates include bisphenol A,
polycarbonate or the like. Examples of thermoplastic polymers
include polyethene (PE), polypropylene (PP) and the like. The
substrate may have UV, IR or VIS light blocking characteristics.
Other examples of substrate materials include ceramic spinel or
aluminum oxynitride.
[0112] The substrate may be of uniform or varying thickness, and of
any suitable dimension. For example, the substrate may have a
thickness from about 0.01 mm to about 10 mm, or any amount or range
therebetween, for example 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9
or 10 mm, or from about 0.012 mm to about 10 mm, or from about 0.5
mm to 10 mm, or from about 1 mm to 5 mm, or from about 0.024 mm to
about 0.6 mm, or from about 0.051 mm (2 mil) to about 0.178 mm (7
mil). In some embodiments, the thickness and/or material of a first
substrate differs from the thickness and/or material of a second
substrate. In some embodiments, a substrate with a conductive layer
may be ITO-coated glass, or ITO-coated PET.
[0113] A transparent conductive layer (electrode) may comprise, for
example, metals, metal alloys, metal oxides, conjugated organic
polymers, conductive carbon-rich materials and fine wire meshes.
Exemplary conductive materials include layers of indium tin oxide
(ITO), doped tin oxide, doped zinc oxide, doped cadmium oxide,
fluorine tin oxide, antimony tin oxide, cubic strontium germanium
oxide, polyaniline, graphene, fullerenes, carbon nanotubes, PEDOT
(poly(3,4-ethylenedioxythiophene)), PEDOT:PSS (poly
(3,4-ethylenedioxythiophene) poly(styrenesulfonate), and
polypyrrole, as well as thin, substantially transparent metallic
layers such as gold, silver, aluminum, and nickel alloy. Methods of
applying the electrically conductive material to a substrate to
form suitable conductive layers and electrodes are known, for
example chemical deposition, sputter coating or the like. The
conductive layer may be of thickness that provides adequate
conductance for operation of the electrodes, and which does not
appreciably interfere with the transmission of light. The thickness
of the conductive layer may be from about 1 nanometer to about 90
microns, or any amount or range therebetween. In some embodiments,
a conductive material may be dissolved in a suitable solvent and
cast in a layer (a transparent conductive layer), and used in a
composite optical filter without being applied to a substrate.
[0114] Thus, there is further provided, in part, a method of making
a switchable film. A first substrate with a conductive coating is
provided, and a flowable switching material disposed thereon. The
switching material may be provided by a dispensing unit and a
distributer to dispose evenly on the surface of the conductive
coating a layer of the switching material. The dispensing unit may
be a syringe, flask or similar container; larger volumes, or
coating methods for intended for continuous or semi-continuous
throughput may necessitate the use of a reservoir and pump,
suitable nozzles or outlets or the like. The distributer may be a
knife or dispensing bar with a machined edge to provide for an even
distribution of switching material of a selected thickness. In
other embodiments, the switching material may be dispensed onto the
surface and later distributed evenly by passing through a
roll-press. For example, following dispensing, and optionally
distributing, the switching material onto the surface, a second
substrate with conductive coating may be applied (with conductive
coating contacting the switching material) to the layer of
switching material, and the `sandwich` of switching material and
substrates with coating passed between a roller nip to press the
sandwich together, to provide an optical filter. The final
thickness may be determined by the gap of the roller nip. For
switching materials that include a co-solvent to provide a suitable
viscosity for coating, the co-solvent may be removed (e.g.
evaporation) before application of the second substrate. For
materials that do not include a co-solvent to provide a suitable
viscosity, no step of evaporation is necessary and the second
substrate may be applied following dispensing and optional
distribution of the switching material. To provide a suitable
viscosity for coating, the switching material (without co-solvent)
may be heated prior to and/or during application, using heated
coating knives or bars, heated reservoir, heated roller nips or the
like.
[0115] Once the switchable film has been made (and cut to shape and
contacts added if desired), it may be laminated between two layers
of an adhesive resin and that between two sheets of glass.
Advantageously, switching materials and films as described herein
may be laminated in glass with hot-melt adhesive layers, using
temperatures and pressures used in conventional glass lamination.
The switchable material and films do not demonstrate increased haze
following heat lamination, A glass-adhesive-switchable
film--adhesive-glass sandwich may be passed through a press roll,
pressed between plates at an elevated temperature (about 90.degree.
C. to about 140.degree. C. --pressure and temperature may be
increased and decreased over several steps), or may be placed in a
bag (rubber), with an initial bonding at a temperature of about
70.degree. C.-110.degree. C., while applying a vacuum to remove air
between the layers. A second bonding step is then performed at a
temperature of about 120.degree. C.-150.degree. C., with pressure
(e.g. about 0.95 to about 1.5 MPa in an autoclave).
[0116] The first and/or second substrates may block, or absorb,
selected ranges or wavelengths of light. In some embodiments the
first and/or second substrates may be treated with, or have applied
to them, a layer or coating that blocks (reflects or absorbs)
selected ranges or wavelengths of light. In some embodiments, the
range or wavelength of light may be in the UV range. Examples of UV
blocking films that may be applied include EnergyFilm.TM.
(described in WO2002/018132) and EnerLogic.TM. (described in
WO2009/087575). In some embodiments the substrate is PET with a
coating that blocks light of wavelengths of about 375 nm or
less.
[0117] In some embodiments, the switching material, or an optical
filter comprising the switching material, may be disposed upon a
pane of glass, or other transparent material suitable for use as a
window, or incorporation into an insulated glazing unit (IGU), or a
storm window or secondary glazing. Methods of making IGU, windows
or the like, and affixing an optical filter to glass or other
suitable material are described in, for example, WO2010/142019 as
are methods of configuring an electrical system and/or control
system for operation (electrofading) of an IGU comprising an
optical filter. In some embodiments, the switching material may be
incorporated into an opthalmic device (e.g. visors, masks, goggles,
lenses, eyeglasses (prescription or not) or the like). In some
embodiments, the switching material may be used in glazing products
such as architectural installations or vehicle (e.g. truck, car,
airplane, train, or the like) installations. Architectural
installations may be external-facing, or internal to the building,
and may include a window, wall (e.g. partition, divider, full or
partial wall, permanent or temporary wall), display (e.g.
illuminated information panels, touchscreens, control panels).
Vehicle installations include windows, sunroofs or other glazings,
including sunroofs of various types including pop-up, spoiler,
inbuilt, folding sunroofs, panoramic roof systems or removable roof
panels. Vehicle windows include windshields, rear windows, side
windows, sidelight windows, internal dividers (movable or not) to
divide the interior space of a vehicle for temporary or permanent
purposes. Electrical power may be provided by a separate battery,
or the device may be connected to an electrical system of the
device--it may be wired into a vehicle or building's electrical
system.
[0118] Kits
[0119] There is further provided, in part, a kit for making a
switching material comprising a switching material, and
instructions for its use. The kit may further comprise an
accelerant; the accelerant may be separately packaged from the one
or more components of the switching material. The switching
material may comprise one or more polymers; the kit may further
comprise an electrolyte, or a salt for combining with a solvent to
provide an electrolyte.
[0120] The kit may comprise the components of a switching material
for making a switching material, the components divided into
multiple parts. A kit may comprise: 1) a first part comprising a
polymer, a salt and a first portion of a solvent; the first part
may further comprise an optional hybrid P/E compound, or the
optional hybrid P/E compound may be provided separately for
combining with the first part; 2) a second part comprising a cross
linking agent, an optional hardener and a second portion of the
solvent; and 3) a third part comprising an accelerator, along with
instructions for combining the parts, and/or conditions for mixing
and adjusting viscosity if needed to provide a coatable switching
material.
[0121] The term "mil" as used herein, refers to the unit of length
for 1/1000 of an inch (0.001). One (1) mil is about 25 microns;
such dimensions may be used to describe the thickness of an optical
filter or components of an optical filter. One of skill in the art
is able to interconvert a dimension in `mil` to microns, and vice
versa.
[0122] "About" as used herein when referring to a measurable value
such as an amount, a temporal duration, and the like, is meant to
encompass variations of .+-.20% or .+-.10%, more preferably .+-.5%,
even more preferably .+-.1%, and still more preferably .+-.0.1%
from the specified value, as such variations are appropriate to
perform the disclosed methods.
[0123] Embodiments are illustrated, in part, by the following
non-limiting methods and examples:
[0124] General Methods
[0125] Mixing Methods
[0126] Preparation of formulation may be performed in an inert
atmosphere, a reduced humidity atmosphere, or in an open
atmosphere.
[0127] Method A: All components except crosslinker were combined
with stirring (85.degree. C., 18-24 hours), in 1-1.5 eq sacrificial
solvent (THF or MEK). The formulation was cooled to RT, and a
solution of crosslinker in solvent was added, with a further 15
minutes of stirring, prior to coating.
[0128] Method B: a first part was prepared by combining
chromophore, PVB, salt and a first portion of the solvent, with
stirring. A second part was prepared by combining cross-linker,
hardener and a second portion of the solvent. First and second
parts were prepared, combined and mixed for 15-24 hours (rotating
oven at 80.degree. C.). A third part comprising sacrificial solvent
and accelerant was prepared (shaking at RT). Parts 1 and 2 were
combined and allowed to cool to RT; part 3 was added, and mixed at
RT for .about.2 hr before coating.
[0129] Method C: a first part was prepared by combining
chromophore, a first PVB, salt and a first portion of the solvent
in a first vial. A second part was prepared by combining a second
PVB, cross-linker, hardener (if used) and a second portion of the
solvent in a second vial. First and second parts were mixed gently
(rotating oven) at 80.degree. C. overnight (15-24 hours). The first
vial was allowed to cool to RT and the accelerant added (a third
part) and the vial returned to the rotating oven for a further 2-4
hours. Parts 1 and 2 were combined and returned to 80.degree. C.,
the hot formulation was transferred to a syringe for coating.
[0130] Coating:
[0131] Coating of substrates may be performed in an inert
atmosphere, a reduced humidity atmosphere, or in an open
atmosphere. Co-solvent may be removed by evaporation. To coat, a
conductive-coated coated substrate (e.g. ITO-PET) was cut to a
desired shape, and a coatable formulation comprising a co-solvent
was coated (knife drawn) onto the conductive side of a first sheet
of ITO-coated PET using ChemInstruments EZ Coater EC-200, with a
Byk coating bar. The co-solvent was evaporated using blown air, and
a second layer of conductive-coated substrate laminated on top of
the coating with the conductive side in contact with the switching
material to form a sandwich structure. The film was rested at room
temperature to cure. Optionally, the cure may be followed by
incubation at 80.degree. C. for about 10 minutes, or overnight. For
compositions without a co-solvent, the step of evaporation was
omitted. For compositions with a UV-curing crosslinker, the coated
formulation was cured by exposure to UV light (395 nm) before
applying the second layer of substrate and conductive oxide.
[0132] Following coating and lamination, edges of the `sandwich`
may be sonically welded to provide a seal, or sealed with a layer
of polyisobutylene (PIB). Electrical contacts may be added for
samples or films that are intended for electrofading.
TABLE-US-00001 TABLE 1 Characteristics of some PVBs. Initial
screening of polymer components included a range of polyols as
listed herein. Several PVBs from a variety of suppliers, including
Aldrich, Solutia and Kuraray were tested. PVOH content PVA content
Reference MW (%) (%) PVB-1 18-28k 18-21 1-4 PVB-2 37-47k 18-21 1-4
PVB-3 50-60k 18-21 1-4 PVB-4 95-105k 18-21 0-4 PVB-5 50-60k 12-16
1-4 PVB-6 250-350k 12-16 6-10 PVB-7 50-60k 24-27 1-4 PVB-8 170-250k
17.5-20.sup. 0-2.5 PVB-9 70-100k 18.5-20.5 0-2.5 PVB-10 40-70k
18-20 0-2.5 PVB-11 12-14 1-4
[0133] Preparation and Lamination of Switchable Film:
[0134] Switching material according to formulations disclosed
herein were prepared, and optionally combined with co-solvent. This
composition was coated on an ITO-coated PET substrate to provide a
final thickness of about 1-2 mil, the co-solvent evaporated and
laminated with a second ITO-coated PET substrate and allowed to
complete curing overnight at 22.degree. C., followed by one hour at
80.degree. C. The `sandwich` structure was cut to the desired size,
sealed and electrical contacts added.
[0135] Glass Lamination:
[0136] Once the switchable film has been made, and busbars and
optional electrical connectors attached, this layer may be attached
with an adhesive to a sheet of glass, or laminated between two
layers of an adhesive resin and that between two sheets of glass. A
"sandwich" of glass-adhesive-switchable film-adhesive-glass was
placed in a Carver press (Carver Inc. Wabash Ind.) and pressed at
.about.55-90 psi at 135.degree. C. for 40 minutes, with ramp-up and
cool down periods of about 10 minutes.
[0137] In another method, the sandwich may be placed in an
evacuated bag, sealed to maintain the vacuum, and incubated in an
oven with an initial bonding at a temperature of about 70.degree.
C.-110.degree. C. An optional, second bonding step may be performed
at a temperature of about 120.degree. C.-140.degree. C., with
pressure (e.g. about 0.95 to about 1.5 MPa in an autoclave).
[0138] The overall thickness of the laminated glass is dependent,
in part on the thickness of the various layers, generally an
overall thickness of about 6.3 to about 6.6 mm is preferred.
Performance of laminated glass or multi-layer compositions as
described herein may be tested by conducting studies using standard
techniques in the art, for example, measurement of VLT, LT.sub.A,
color, haze, switching speed, photostability, and/or durability.
WO2010/142019 describes methods, equipment and techniques that may
be used to assess the performance of optical filters.
[0139] Photochemical Darkening and Fading; Electrochemical
Fading
[0140] Laminated glass or multi-layer compositions are exposed to
UV light to darken the switching material, resulting in a decrease
in the light transmittance of the material in the visible range. An
electric charge of about 2 Volts is then applied to the switching
material for 3 minutes, causing the switching material to switch to
a faded state. In the faded state, more light is permitted to pass
through the switching material resulting in an increase in light
transmittance in the visible range. VLT or LT.sub.A in both dark
and faded states is measured using an Ocean Optics spectrometer,
and a contrast ratio may be calculated (LT.sub.A faded
state/LT.sub.A dark state).
[0141] Photostability:
[0142] For photostability assessment, samples were prepared in SGC
and weathered in a QSUN Xenon Test Chamber (Q-Labs) at 0.68
W/m.sup.2. Devices were initially darkened on the QSUN for 1 hour
and an initial dark state transmission spectrum (darkening
performance) obtained using an Ocean Optics spectrometer. Each
device was subsequently photo-faded using a low pressure sodium
lamp with yellow filter (400-500 nm cutoff), and an initial faded
state transmission spectrum obtained (baseline for yellowness
index, and for darkening performance). Devices were returned to the
QSUN and spectra taken twice weekly until failure. A device was
considered `failed` when a change in Yellowness Index (.DELTA.YI)
greater than 15 from baseline and/or a decrease in darkening
performance of 20% or greater, relative to baseline was
observed.
[0143] A sintered glass cell (SGC) is an enclosed glass chamber
with first and second electrodes on opposing inner surfaces, the
first and second electrodes electrically separated from each other,
and individually connected to a power source for application of a
voltage to material placed within the assembled chamber. SGC
devices are sealed with nitrocellulose and low-melt glass powder by
baking at .about.500.degree. C. Injection ports facilitate
placement of material within the assembled chamber, and may be
sealed with a Teflon plug and held in place by a clamp.
[0144] Cyclic Voltammetry (CV):
[0145] CV was conducted using a three-electrode setup with a 2 mm
Pt disc working electrode, a Pt wire counter electrode and an
Ag/Ag+ reference electrode. The three-electrode setup was placed
into the electrolyte and voltammograms were acquired by scanning a
potential window from about -1.0 volts to +2.0 volts, with a scan
rate of 100 mV/s. Peak potentials were referenced using ferrocene
as an internal standard at the end of each experiment. The Pt disc
electrode was cleaned between each experiment by polishing with 1
um and 0.5 um diamond paste followed by sonication in distilled
water then rinsed with ethanol and air dried. All experiments were
performed at ambient temperatures (25.degree. C.). Where CV is used
to identify suitable solvents, the electrolytic solution (solvent
and electrolyte), should have a background scan without any major
redox peaks, <2.5 .mu.A/mm.sup.2, in a potential window of about
-1 to about 1.2 V, vs Ag/Ag+ reference electrode.
Example 1: Switchable Formulations--Solvent Selection
[0146] The "Alpha 2" class of formulations comprise triglyme as a
solvent component, TBABF.sub.4 or TBAPF.sub.6 as a salt, PMMA or
PVB or a combination thereof as rheology modifiers, and 5-10 wt %
of chromophore. Selected examples of formulations within the Alpha
2 class are set out in WO2010/142019. The Alpha 2.5 formulation is
a viscous, switching material comprising PVB-9 (21.9 wt %),
triglyme (67.6 wt %), 0.5 wt % TBABF.sub.4 and 10% chromophore. At
elevated temperatures and/or pressure, alpha 2 class formulations
may decrease in viscosity, and exhibit flow.
[0147] Switchable materials that resisted flow at elevated
temperatures may be useful for some applications. Alpha 4.x, 5.x
and 6.x formulations are crosslinked to increase the resistance to
flow under elevated temperature and/or pressure. The "Alpha 4"
group of formulations comprise PDMS-g-PEG, PMMA (350 kDa), PEG-DMA
(750 Da), PEG-MEMA (475 Da), triglyme, 5-10% chromophore,
TBABF.sub.4 and Irgacure 819, and are UV cross-linked. The Alpha
4.2 formulation is a UV cross-linked switching material comprising
PDMS-g-PEG (1 wt %), PMMA (350 kDa) (7 wt %), PEG-DMA (750 Da)
(12.45 wt %), PEG-MEMA (475 Da) (12.45 wt %), triglyme (56 wt %),
10 wt % chromophore, TBABF.sub.4 (0.1 wt %) and Irgacure 819 (1 wt
%), Briefly, PDMA, salt, triglyme and PMMA are mixed at 80.degree.
C. Chromophore was subsequently added and dissolved in the premix
with stirring at 80.degree. C., and the mixture cooled to ambient
temperature. PEG-DMA and PEG-MEMA were subsequently added with
stirring at ambient temperature, with a minimum 1 hour of mixing.
Irgacure 819 was added, stirred for 10 minutes at ambient
temperature and the formulation coated and cured with UV light (3
min exposure, 35 mm gap; RX StarFire 150.times.20 mm emitting
window; AC395-1.75W from Phoseon Technologies)
[0148] The Alpha 5 group of formulations comprise
epoxide-cross-linked PVB in an electrochromic medium, the
electrochromic medium comprising a salt and a solvent. The Alpha
5.1 formulation is a switching material comprising S109 (10%),
diethyl adipate (DEAd) or dimethyl adipate (DMAd) (77.6%), AMC-2
(0.8%), DER736 (0.8%), MHHPS (0.7%), TBABF.sub.4 (0.1%), PVB-9
(1%), PVB-3(9%). The alpha 5.x series formulations include Texanol
as a solvent.
[0149] Solvent Selection: A preliminary screen of solvents was
conducted by assessing the photostability of a 10% solution of
chromophore in the solvent. Solvents that did not demonstrate
suitable photostability, were removed from further
consideration.
[0150] Additional solvents identified as having one or more of a
boiling point of about 150.degree. C. or greater, a vapour pressure
of about 0.001 mmHg or less at 20.degree. C., a flash point of
about 80.degree. C. or greater, a melting point of about 40.degree.
C. or less were tested for compatibility with selected formulation
components--S109 (10%); TBABF.sub.4 (1%); PVB-9 (5%); PMMA 350 kDa
(5%); PEG-DMA 750 Da (50%); PEG-MEMA 375 Da (50%); Irgacure 819
(1%); and PDMS-g-PEG (1%). Solubility of formulation components and
optical clarity of the resulting solution were the initial criteria
assessed. A compatible, or suitable, solvent was one that dissolved
all components of at least one of alpha 2, alpha 4 or alpha 5 class
formulation, and was optically clear.
[0151] Suitable solvents were further assessed for cyclic
voltammetry (CV) performance, and photostability (PS) with S109 and
S158 chromophores. Solvents demonstrating suitable solubility
profiles were further screened using cyclic voltammetry (CV).
Solvents demonstrating suitable CV profiles were screened for
photostability with and without chromophore. Results of solubility,
CV and initial PS screen candidate solvents for use with one or
more of alpha 2, alpha 4 or alpha 5 formulations are set out in
Table 2.
TABLE-US-00002 TABLE 2 Solvent selection - solvents demonstrating
alpha 2 (a2), alpha 4 (a4) and alpha 5 (a5) component solubility,
suitable CV profile and suitable PS profile for S109 and S158
chromophores. S109 S158 Solvent a 2 a4 a5 CV PS PS Triglyme
1-Decanol 2-(2-ethylhexyloxy)ethanol (EHE)
2,2,4-trimethyl-1,3-pentanediol monoisobutyrate ("Texanol")
2,2,4-trimethyl-1.3-pentanediol dibenzoate 2-Ethyl-1,3-hexanediol
(2E13H) 2-ethylhexyl-(s)-lactate (EHL)
3-(hydroxypolyethyleneoxypropyl)- heptamethyltrisiloxane
Di(ethylene glycol) dibenzoate Di(propylene glycol) dibenzoate
Dibutyl itaconate (BI) Diethyl adipate (DEAd) Diethyl azelate
diethyl phthalate Diethyl succinate diethylene glycol hexyl ether
(DEGHE) diethylene glycol monobutyl ether Diethylene glycol
monoethyl ether acetate (DEGEEA) diethylene glycol n-butyl ether
acetate (BEEA) dimethyl adipate (DMAd) dimethyl azelate dimethyl
phthalate Dimethyl-2-methyl glutarate dipropylene glycol
dipropylene glycol methyl ether acetate Dipropylene glycol
monomethyl ether dipropylene glycol n-butyl ether Dipropylene
glycol n-propyl ether ethylene glycol phenyl ether (POE) Glyceryl
triacetate N,N-dimethyldecanamide poly(ethylene glycol) dibenzoate
poly(propylene glycol) dibenzoate propylene carbonate (PC)
Propylene glycol diacetate (PGDA) tetraethyl
propane-1,1,2,3-tetracarboxylate tetramethylene sulfone
Tetramethylene sulfoxide Tri(propylene glycol) butyl ether
Tri(propylene glycol) methyl ether Tributyrin aka Butanoic acid,
1,2,3-propanetriyl ester Triethylene glycol di-2-ethyl butyrate
(TEG DEB) triethylene glycol monobutyl ether triethylene glycol
monoethyl ether (TEG MEE) triethylene glycol monomethyl ether(TEG
MME) tripropylene glycol Tripropylene glycol n-propyl ether
(TPGPE)
[0152] FIGS. 1 and 2 illustrate the darkening performance and
change in Yellowness Index respectively, for all solvents with a
suitable CV profile in the presence of S109 (5%). Solvent is
indicated along the X axis. An initial baseline of fully darkened
and fully faded state was taken as described, and samples were
assessed regularly for darkening performance as reaching 90-100% of
baseline, 85-90% of baseline, 80-85% of baseline, and fail
(reaching less than 80% of baseline); and for change in Yellowness
Index (A (delta) YI). Samples are indicated as having a .DELTA.YI
of 0 to 5 points off baseline, 5-10 points off baseline, 10-15
points off baseline, and fail (beyond 15 points of baseline). The
darkening performance and .DELTA.YI of solutions containing S109
and S158 were assessed in a subset of solvents (BEEA, BI, DEAd,
DMAd, PGDA, IRIS, Texanol and triglyme) that demonstrated the best
darkening performance and .DELTA.YI. Results are shown in FIGS. 3
and 4.
Example 2: Aldehyde Crosslinking of Switchable PVB Formulations
[0153] Irgacure 819 (used in alpha 4 class formulations) is a
photoinitiator for radical polymerization of polymers upon UV
exposure (UV cross-linking). Alternate polymer crosslinking
methods, and different polymers were investigated. The Alpha 5
class of formulations were developed to crosslink without a radical
(UV) cure. Switchable aldehyde-crosslinked formulations were
developed, comparing two different acid cures, and inclusion of a
`water scavenger` (triethyl orthoformate). Formulations are recited
in Table 3. Formulations were prepared and coated in a reduced
humidity and reduced oxygen environment (nitrogen- or argon-filled
glove box with less than 100 ppm atmospheric water and less than
100 ppm oxygen).
TABLE-US-00003 TABLE 3 Aldehyde crosslinked formulations #1 to #3
Formulation #1 Formulation #2 Formulation #3 triglyme 84.55 82.93
82.55 PVB-9 5 4.88 5 Terephthalaldehyde 0.3 0.3 0.3 HCl -- 0.1 1
p-toluenesulfonic acid 0.05 -- 0.05 S109 10 9.76 10 TBABF.sub.4 0.1
0.1 0.1 Triethyl orthoformate -- 1.95 2 All quantities in wt %.
[0154] Components for formulation #1 to #3 (except acid --HCl or
pTSA) were combined and mixed at 80.degree. C. for 20 min, and
rested overnight (RT). The resulting semi-solid mixture was
re-heated to 80.degree. C., and the acid added with stirring, and
the formulation injected into a sintered glass cell (SGC) and cured
for 24 hours at 80.degree. C.
[0155] Following curing, all three formulations were reversibly
interconvertible from a light state to a dark state and from a dark
state to a light state by exposure to UV light and application of a
voltage (.about.2 volts), respectively.
Example 3: Epoxide Crosslinking
[0156] Switchable epoxide-crosslinked PVB formulations were
developed, using solvents demonstrating an improvement in darkening
performance and/or .DELTA.YI, relative to triglyme. Composition of
formulations #4 to #10 are provided in Table 4. Mixing and coating
was performed as described according to Mixing Method A.
[0157] Formulation #4 did not include an accelerant. The film was
coated in ambient atmosphere, with the goal of determining if the
uncured switching material was hard enough to laminate. Following
evaporation of the co-solvent (THF) the formulation oozed from the
side of the film when the second layer of substrate was
applied.
[0158] Formulation #5 was composed, coated, and co-solvent
evaporated. The resulting switching material was successfully
laminated and was cured as described. The resulting `sandwich` did
not electrofade.
[0159] Formulation #6 provided 10% total PVB content after
evaporation of co-solvent, and was coatable and laminatable after
evaporation of co-solvent, and was cured as described. The
resulting `sandwich` did not electrofade.
[0160] Formulation #7, 8, 9 and 10 were coatable, and following
evaporation of co-solvent, was laminated and cured as described.
The resulting `sandwich` was successfully electrofaded.
[0161] FIGS. 5 and 6 show a comparison of alpha 2.5, alpha 4.2
formulation, and two alpha 5.1 formulations (formulations #8 and
10) for darkening performance and .DELTA. YI. Alpha 2.5--(Device
3430) S109 10%, TBABF.sub.4 0.5%, PVB-9 21.9%, triglyme 67.6%.
Alpha 4.2--(Device 3352) S109 10%, TBABF.sub.4 0.1%, Irgacure 1%,
PEG-DMA 12.45%, PMMA 7%, PDMS-g-PEG 1%, PEG-MEMA 12.45%, triglyme
56%. Alpha 5.1a with DEAd--(Device 4409) S109 10%, Diethyl Adipate
77.6%, AMC-2 0.8%, DER736 0.8%, MHHPA 0.7%, TBABF.sub.4 0.1%, PVB-9
1%, PVB-3 9%. Alpha 5.1b with DMAd--(Device 4404) S109 10%,
Dimethyl Adipate 77.6%, AMC-2 0.8%, DER736 0.8%, MHHPA 0.7%,
TBABF.sub.4 0.1%, PVB-9 1%, PVB-3 9%. Alpha 5.1 formulations
demonstrated superior darkening performance relative to alpha 2.5
and 4.2; the experiment was terminated before the alpha 5.1 samples
reached failure. Alpha 4.2 appeared to have an overall superior
.DELTA. YI performance, however the time to progress beyond a
.DELTA. YI of 5 was not improved over either of alpha 5.1
formulations.
[0162] Formulation components for Alpha 6.1f, alpha 7.0, alpha 8.1,
alpha 8.1b and alpha 9.1 are provide in Tables 8, 9 and 10, and
Example 9.
TABLE-US-00004 TABLE 4 Formulations #4-#10 formulation 4
formulation 5 formulation 6 formulation 7 formulation 8 formulation
9 formulation 10 Wt % WWC Wt % WWC Wt % WWC Wt % WWC Wt % WWC Wt %
WWC Wt % WWC DEAd 60.08 39.95 49.60 24.80 64.56 32.27 75.65 60.50
77.60 51.73 DMAd 77.60 51.73 BEEA 77.60 51.73 S109 10.08 6.70 10.00
5.00 10.00 5.00 10.02 8.01 10.00 6.67 10.00 6.67 10.00 6.67 PVB-3
15.12 10.05 25.00 12.50 9.00 4.50 9.02 7.21 9.00 6.00 9.00 6.00
9.00 6.00 PVB-9 1.00 0.50 1.00 0.80 1.00 0.67 1.00 0.67 1.00 0.67
TBABF4 0.50 0.34 0.50 0.25 0.50 0.25 0.50 0.40 0.10 0.07 0.10 0.07
0.10 0.07 DER 736 7.86 5.23 7.80 3.90 7.80 3.90 1.65 1.32 0.80 0.53
0.80 0.53 0.80 0.53 MHHPA 6.35 4.22 6.30 3.15 6.30 3.15 1.35 1.08
0.70 0.47 0.70 0.47 0.70 0.47 AMC-2 0.80 0.40 0.80 0.40 0.80 0.64
0.80 0.53 0.80 0.53 0.80 0.53 100.00 66.49 100.00 50.00 100.00 50
100.00 80 100.00 66.67 100.00 66.67 100.00 66.67 THF -- 33.51 MEK
50 50 20 33.33 33.33 33.33 WWC--wt % with cosolvent
Example 4: Epoxide Crosslinking
[0163] Texanol had also demonstrated suitable darkening performance
and .DELTA. YI in earlier studies. Formulations were mixed and
coated as described and cured by incubation at 50.degree. C.
overnight (15-18 hr)--specific components are set out in Table 5
(wt %).
TABLE-US-00005 TABLE 5 Alpha 5.x formulations Component 5.4 5.3
5.5a 5.5b 5.6 5.6a 5.6b PVB-8 8.5 8.5 8.3 8.3 7.82 7.67 7.8 Texanol
79.1 79.1 77.4 76.3 72.88 71.53 71.8 S109 10 10 10 10 15 15 15 DER
736 0.8 0.8 0.8 1.2 0.8 0.8 1.2 MHHPA 0.7 0.7 0.7 1 0.7 0.7 1 AMC2
0.8 0.8 0.8 1.2 0.8 0.8 1.2 TBATFSI -- -- 2 2 3.5 2 TBABF4 0.1 0.1
2 Total 100 100 100 100 100 100 100 MEK -- 50% wt
Example 5: Comparison of Epoxides
[0164] A selection of epoxides were tested for effect on cure time
and any effect on properties of the resulting film (clarity, flow,
etc). A formulation containing 56.09 wt % Texanol, 6.01 wt % PVB-8,
0.51 wt % MHHPA, 0.58 wt % AMC-2, 36.23 wt % MEK and 0.058% epoxy
was mixed and coated as described. DER736 was used as a comparison.
Cure times are indicated in Table 6.
TABLE-US-00006 TABLE 6 Comparative cure times for various epoxies
(relative to DER736). cure time vs Epoxy Der 736 DER736 --
1,4-cyclohexanedimethanol diglycidyl ether slower 1,4-butanediol
diglycidyl ether same 1,7-octadienediepoxide same
1,2,5,6-diepoxycyclooctane same no epoxy slower ethylene glycol
diglycidyl ether same neopentyl glycol diglycidyl ether same
bisphenol A diglycidyl ether same tris(4-hydroxyphenyl)methane
triglycidyl ether same resorcinol diglycidyl ether same
[0165] Time to cure was assessed by a peel test (pulling opposing
substrates in opposite directions and observing behaviour of the
switchable material)--cohesive failure was scored as a complete
cure; uncured or incompletely cured material remained adhered to
both substrates and was stretched as they separated. Samples were
assessed every 30 minutes over the course of up to 4 hours, or
until cure.
Example 6: Comparison of Accelerant
[0166] A selection of accelerants were tested for effect on cure
time and effect on properties of the resulting film (clarity, flow
etc). A formulation containing 56.09 wt % Texanol, 6.01 wt % PVB-8,
0.51 wt % MHHPA, 0.58 wt % DER736, 36.23 wt % MEK and 0.058%
accelerant was prepared and coated as described. Cure times for
formulations with different accelerants are indicated in Table 7,
relative to AMC-2. Time to cure was assessed by a peel test of the
substrates as described.
TABLE-US-00007 TABLE 7 Comparative cure times for various
accelerants (relative to AMC-2). active cure Accelerant metal time
AMC-2 Cr -- ATC-2 Cr same CXC-1613 Zn same TYZOR ZEC Zr same Zn
octanoate Zn same Cr 2-ethylhexanoate Cr same in mineral oil AC-8
unknown same
Example 7: Isocyanate Crosslinking of Switchable PVB
Formulation
[0167] Isocyanate crosslinking of PVB was evaluated as an
alternative for epoxide systems. Formulations varying switching
compound (S109 or S158) and salt were prepared and tested, and
films cast and observed for ability and rate of switch between dark
and faded states. Curing of the system was done at room
temperature. Table 8 sets out examples of isocyanate cure
formulations.
TABLE-US-00008 TABLE 8 Alpha 6.x formulations. All quantities are
wt %. 6.0 6.0a 6.0b 6.0c 6.1 6.1a 6.1b 6.1c 6.1d 6.1e 6.1f 6.1g
PVB-8 7 7 7 7 7 7 7 6.43 7 7 6 6 Texanol 80.79 80.79 80.79 80.79
75.19 75.19 73.69 74.26 75.79 74.29 76.79 76.79 S109 10 10 15 15 15
15 15 15 15 S158 10 10 15 Desmodur 0.2 0.2 0.2 0.2 0.8 0.8 0.8 0.8
0.2 0.2 0.2 0.2 N3600 Zinc 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01
0.01 0.01 0.01 0.01 Octanoate TBATFSI 2 2 2 2 3.5 3.5 2 3.5 2 2
TBABF4 2 2 Total 100 100 100 100 100 100 100 100 100 100 100
100
[0168] A co-solvent free formulation may be mixed in two parts
(separating the isocyanate and accelerant).
Example 8: Combined Solvent Formulations
[0169] Inclusion of a second solvent to increase the switching
speed was investigated. [0170] Combining Texanol (dielectric
constant .epsilon..apprxeq.2) with a second solvent with a high
dielectric constant may promote more efficient disassociation of
the salt, thereby increasing the rate of electrochemical oxidation
of the ring-closed hybrid P/E compound resulting in conversion to
the a ring-opened state. 1,2-Butylene carbonate (BC) or
.delta.-valerolactone (VL) (.epsilon.>30) were incorporated in
the solvent portion of an alpha 6.2 formulation in a 9:1 (w/w)
Texanol: BC or 9:1 (w/w) Texanol: VL mixtures (alpha 6.2) and cast
into films as described. These mixed solvent films demonstrated up
to 50% decrease in LT.sub.A half-life (decreased photostability),
compared to alpha 6.x films using only Texanol (alpha 6.1g).
[0171] Alpha 6.2 included 5109 (15 wt %), Zn Octoate (0.01 wt %),
Desmodur N3600 (0.2 wt %), TBATFSI (2 wt %), PVB-8 (6 wt %), BC
("alpha 6.2BC") or VL ("alpha 6.2VL") (7.68 wt %), Texanol 69.11 wt
%). Alpha 7.0 included 5109 (15 wt %), AMC-2 (0.8 wt %), DER 736
(0.8 wt %), MHHPA (0.7 wt %), TBA TFSI (2 wt %), PVB-8 (7.82 wt) %,
1,2-Butylene carbonate (7.29 wt %), Texanol (65.59 wt %). FIGS. 5
and 6 show the darkening performance and change in yellowness
index, relative to other formulations.
[0172] A comparison of the electrofading kinetics of various films
including alpha 6.2 with BC or VL is provided in Table 14. A
benefit in electrofading kinetics is observed with inclusion of a
solvent portion component with a higher dielectric constant. In
subsequent studies, VL was shown to polymerize to a solid when
heated with a catalyst (85.degree. C. with mixing; 0.2 wt % Zn
Octoate, 99.8 wt % VL). In contrast, BC (99.8 wt % BC, 0.2 wt % Zn
Octoate) did not change in viscosity after 4 days of mixing.
Example 9: Alpha 8.x and Alpha 9.x Formulations
[0173] Texanol is a mixture of isomers of
2,2,4-trimethyl-1,3-pentanediol, one of which is a primary alcohol.
Alpha 8 and 9 formulations were prepared to demonstrate solvent and
polymer combinations without Texanol.
[0174] Alpha 8 formulations were successfully cured, and were
laminatable at elevated temperature and/or pressure with the
exception of formulation 8.4d4 (Tables 10, 14). Specific amendments
to the formulations were made to test, or demonstrate different
characteristics of the films or individual components. For example,
HMDI was substituted with Desmodur N3600 (an HMDI trimer) PVB-8 was
substituted with PVB-4 (to use a more soluble polymer); PVB-5 and
PVB-4 were replaced with PVB-6 (to use a higher MW polymer); salts
with TFSI and BF4 anions were compared for effect on photostability
and electrofading kinetics; crosslinking agent was reduced to
improve kinetics.
[0175] Alpha 9 formulations (Table 9) were successfully cured and
were laminatable at elevated temperature and/or pressure. Alpha 8
formulations (Table 10) were successfully cured; in an inert
atmosphere (N2 glove box) or under normal atmosphere with reduced
humidity.
TABLE-US-00009 TABLE 9 Alpha 9 formulations. All quantities in wt
%. 1-1.5 eq THF was used as co-solvent for all formulations. GPOx -
glycerol propoxylate- block-ethoxylate (Mn ~4000); SOLEF - SOLEF
21508 (Solvay). Alpha 9.1, 9.1a and 9.1c were shown to be
laminatable, representing both ranges of crosslinker used in the
alpha 9 formulations. 9.1 9.1a 9.1b 9.1c 9.1d S109 S158 10 10 10 10
10 ZnOct 0.1 0.1 0.01 0.01 0.1 N3600 0.62 0.47 0.62 0.47 0.62
TBATFSI 1 1 1 1 TBABF4 1 SOLEF 10 10 10 10 10 GPOx 5 5 5 5 5 BC
7.33 7.34 7.34 7.35 7.33 RI 65.95 66.09 66.03 66.17 65.95
TABLE-US-00010 TABLE 10 Alpha 8 formulations. All quantities in wt
%. 1-1.5 eq THF was used as co-solvent for all formulations. All
resulting films darkened with exposure to UV light, and faded with
application of 1.8-2.5 V. Relative performance is shown -
electrofading kinetics (1 = Poor, 2 = Fair, 3 = Good) and
lamination ("Lam") - pass/fail. ND no data. 8.1 8.1a 8.1b 8.2 8.2a
8.2b 8.3 8.3a 8.3b 8.3c S109 15 15 15 S158 15 15 15 15 15 15 S161
15 ZnOct 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 N3600
0.08 0.08 0.28 0.28 0.28 0.28 HMDI 3.75 0.37 3.75 0.37 TBA-TFSI 1 1
1 1 1 1 1 1 1 TBA-BF4 1 PVB-8 3 3 10 PVB-5 10 10 10 10 10 3 PVB-4 3
3 3 PVB-6 10 10 10 10 BC 6.7 7 7 6.7 7 7 7.37 7.37 7.37 7.37 RI
60.54 63.62 63.91 66.34 66.34 66.34 66.34 DES 60.54 63.62 63.91
Kinetics ND Lam Pass Pass Pass Pass Pass Pass Pass Pass Pass ND
8.3z 8.4 8.4a 8.4c 8.4d 8.4e 8.4f 8.4g 8.4h 8.4j S109 15 15 S158
15.2 15 12 15 12 12 15 15 S161 ZnOct 0.01 0.01 0.01 0.01 0.01 0.02
0.02 0.02 0.02 0.01 N3600 0.28 0.21 0.21 0.21 0.21 0.42 0.42 0.21
0.21 0.21 HMDI TBA-TFSI 1.02 1 1 1 1 1 1 1 1 1 TBA-BF4 PVB-8 5 5 5
5 5 5 5 5 5 PVB-5 PVB-4 PVB-6 10.1 7 7 7 7 7 7 7 7 10 BC 7.33 7.18
7.48 7.48 7.46 7.46 7.48 RI 65.97 64.6 67.3 71.78 64.3 67.1 67.1
67.29 71.77 68.78 DES Kinetics ND 3 3 3 3 1 1 3 3 1 Lam Pass Pass
Pass Pass Pass Pass Pass Pass Pass ND
[0176] FIGS. 5 and 6 show a comparison of representative alpha 2.5,
alpha 4.2, alpha 5.1, alpha 6, alpha 7, alpha 8 and alpha 9
formulations for darkening performance and .DELTA. YI. Chemically
crosslinked formulations (alpha 5.1, 5.1b, 6.1f, 7.0, 8.1, 8.1b and
9.1) demonstrated superior darkening performance relative to alpha
2.5 and 4.2. Alpha 4.2 appeared to have an overall superior .DELTA.
YI performance, however the time to progress beyond a .DELTA. YI of
5 was not improved over either of alpha 5.1 formulations. A
decrease in photostability was not observed in alpha 8 and 9
formulations, which omitted Texanol. Removal of TBATFSI salt from
Alpha 6.1f resulted in a formulation with improved darkening
performance, but renders the formulation not electrochemically
switchable. Alpha 8.1, containing Rhodiasolv IRIS and TBATFSI salt
exhibits improved darkening performance over Alpha 6.1f and is
electrochemically switchable.
Example 10: PVB Combinations in Switchable Films
[0177] Stock solutions of 15 wt % PVB-6 and 10 wt % PVB-8 in 9:1
RI:BC, with 1 eq THF were prepared and combined in various ratios
(with additional 9:1 RI/BC solvent portion as needed) to provide a
set of PVB/plasticizer mixtures for test films with 0 or 5-15 wt %
PVB-6 and 0-6 wt % PVB-8. Mixtures were coated as described, rested
overnight and subjected to a peel test for cohesive/adhesive and
firmness (deformation under manual pressure--fingertip or pen).
Results are set out in Table 11. Combinations of polymer that
demonstrate cohesive failure, and score as `firm` were further
tested in alpha formulations with crosslinking (Table 12).
TABLE-US-00011 TABLE 11 plasticizer/polymer mixtures and film
texture. wt % wt % Failure type; sample PVB-6 PVB-8 firmness 1 0 5
Adhesive 2 0 4 Adhesive 3 0 3 Adhesive 4 0 2 (not prepared) 5 10 3
Cohesive; soft 6 10 2 Cohesive; soft 7 10 1 Cohesive; soft 8 9 4
Adhesive 9 9 3 Cohesive; soft 10 9 2 Cohesive; firm 11 8 4
Cohesive; firm 12 8 3 Cohesive; firm 13 8 2 Cohesive; soft 14 7 5
Cohesive; firm 15 7 4 Cohesive; soft 16 7 3 Cohesive; soft 17 6 6
Cohesive; firm 18 6 5 Adhesive 19 5 6 Adhesive 20 5 5 Adhesive 21
15 0 Cohesive; firm
TABLE-US-00012 TABLE 12 Post-cure performance. Formulations
included 15 wt % chromophore (S109), 1 wt % salt (TBATFSI), 0.01 wt
% accelerant (ZnOct), 0.28 wt % N3600, and 68-71 wt % 9:1 RI/BC, in
1 eq. THF co-solvent. wt % wt % Flow after Sample PVB-6 PVB-8
Firmness cure 22 9 3 Soft N 23 8 4 Firm Slight 24 9 2 Soft Slight
25 8 3 Soft N 26 7 5 Firm N 27 6 6 Firm N 28 15 0 Firm N
Films that appeared firm and didn't show flow during post-cure were
tested for electrofading kinetics. Sample 26 was significantly
faster than samples 27 or 28.
Example 11: Deformation Resistance of Switchable Films
[0178] Films were prepared, and placed in a Carver press with a
rubber disc centred on the platen. The disk was compressed against
the film for 10 seconds (at room temperature), and the film
inspected for deformation. A film was considered deformed if it
demonstrated denting, extrusion of film components, or a partial or
full compression ring (switching material squeezed out where the
rubber disc was pressed. An alpha 8.4a film exhibited deformation
with application of 1000 lb force. An alpha 6 film exhibited no
deformation up to 1600 lb of force; application of 1800 lb of force
caused a ring-shaped deformation with material forced outwards,
creating a darker ring (film components pushed out)
Example 12: Electrofading Kinetics
[0179] Inclusion of BC in the solvent portion was found to decrease
the fade time of films. BC was initially excluded as a solvent
candidate as it did not solubilize the chromophore. Surprisingly,
inclusion of BC in the solvent portion improved the fading times of
films, particularly for electrolyte comprising RI and BF4 anion.
Fade times for the indicated formulations are provided in Table 13.
With TFSI as the anion, electrofading kinetics are not greatly
improved with inclusion of BC in the electrolyte. Where the anion
is BF4, inclusion of BC does improve the electrofading time of the
film. Inclusion of BC also improved electrofading kinetics when
combined with Texanol, for either of BF4 or TFSI anions. Haze was
also measured for the indicated films, using a BYK Hazemeter.
TABLE-US-00013 TABLE 13 Thickness, and electrofading time of
switchable films. 90-10% PSS - time in seconds to fade film from
90% of PSS maximum absorbance to 10% of PSS maximum absorbance,
with application of 1.8 V Thickness 90-10% Formulation (mil) PSS
6.1f 1.4 25 6.2BC 1.6 14 6.2VL 1.2 15 5.5a 1.1 122 7.0 1.2 77 8.4a
1.2 15.9 8.4c 1.15 18.5 8.4c1 1.1 19.5 8.3a 1.65 41.0 8.3a* 1.65
46.6 *70.03 wt % RI and 3.68 wt % BC to provide a 19:1 wt ratio
Example 13: Degree of Crosslinking and Effect on Lamination and
Electrofading Kinetics
[0180] Formulation alpha 8.4d was shown to have good electrofading
kinetics, and was laminatable (Table 10). Reducing the quantity of
crosslinker improved electrofading kinetics, but the resulting
films were only laminatable above 0.07 wt % crosslinker (Table 14).
Without wishing to be bound by theory, reducing the crosslinking
may provide a more open film matrix, facilitating movement of
chromophore and ions therein, but with a corresponding reduction in
physical strength.
TABLE-US-00014 TABLE 14 Alpha 8.4d base formula, with varying
crosslinker (N3600) quantities, and response of electrofading
kinetics (1 = Poor, 2 = Fair, 3 = Good) and lamination ("Lam") -
pass/fail. 8.4d1 8.4d2 8.4d3 8.4d4 8.4d5 8.4d6 S109 15 15 15 15 15
15 ZnOct 0.01 0.01 0.01 0.01 0.01 0.01 N3600 0.28 0.21 0.14 0.07
0.25 0.23 TBATFSI 1 1 1 1 1 1 PVB-8 5 5 5 5 5 5 PVB-6 7 7 7 7 7 7
BC 7.171 7.178 7.185 7.192 7.174 7.176 RI 64.539 64.602 64.665
64.728 64.566 64.584 Kinetics 1 3 3 3 2 3 Lam. Pass Pass Pass Fail
ND ND
Example 14: PVB Loading and Effect on Electrofading Kinetics and
Haze
[0181] The loading of PVB-6 in the formulation was increased from
7% (8.4c) to 10% (8.4j) to increase the viscosity of the switching
material in the uncured state to allow the layer of switching
material to pass through a roller nip in a lamination unit of a
roll-to-roll coating machine without altering film thickness due to
the nip pressure. Surprisingly, the haze and electrofading kinetics
were not negatively impacted by the increased PVB content and
decreased solvent content. As electrofading may be rate-limited by
diffusion of molecules in the switching material, increasing the
polymer content, decreasing the solvent content or increasing the
degree of crosslinking (increasing the amount of crosslinking
agent), may result in a switching material where a slower
chromophore diffusion rate and therefore slower electrofading
kinetics may be expected.
TABLE-US-00015 TABLE 15 Electrofading times and haze values for
films of varying PVB-6 content and film thickness. Electrofading
Thickness Times for 90-10% Haze Formulation (mil) PSS (sec) (%)
8.4c 1.2 19 1.68 8.4c 1.0 19 1.82 8.4j 1.0 20 0.94 8.4j 1.1 22 1.56
8.4j 1.2 22 1.88
Other Embodiments
[0182] It is contemplated that any embodiment discussed in this
specification can be implemented or combined with respect to any
other embodiment, method, composition or aspect, and vice
versa.
[0183] The present invention has been described with regard to one
or more embodiments. However, it will be apparent to persons
skilled in the art that a number of variations and modifications
can be made without departing from the scope of the invention as
defined in the claims. Such modifications include the substitution
of known equivalents for any aspect of the invention in order to
achieve the same result in substantially the same way. Numeric
ranges are inclusive of the numbers defining the range. In the
specification, the word "comprising" is used as an open-ended term,
substantially equivalent to the phrase "including, but not limited
to," and the word "comprises" has a corresponding meaning. As used
herein, the singular forms "a", "an" and "the" include plural
referents unless the context clearly dictates otherwise. Citation
of references herein shall not be construed as an admission that
such references are prior art, nor as any admission as to the
contents or date of the references. All publications are
incorporated herein by reference as if each individual publication
was specifically and individually indicated to be incorporated by
reference herein and as though fully set forth herein. The
invention includes all embodiments and variations substantially as
hereinbefore described and with reference to the examples and
drawings.
[0184] Unless defined otherwise, all technical and scientific terms
used herein have the same meaning as is commonly understood by one
of ordinary skill in the art to which this invention belongs.
* * * * *